Hummer Trivia & Misc Info

If this site has helped you consider a Donation. Donation Info
Hummer's Cost? On board Diagnostics PCM Diesel Engine Braking Non Standard Paint
Mileage? Transfer case changes Scratch Protection Dash Pad Grommets
Dealership Design Dual Locking Gas Caps Interior Vinyl Crawl Ratios
How Many are There? Diesel Fuel Additives Repair Roof Rust Canadian Conversion DRL
History 1997 vs 1997.5 Brake Fluid CTIS Leaks
CTI Pump Rubber Mounts Snow Plow Normal Oil Pressure Flasher for LED's
CTI Front Line Leak Fix Hummer Rivets / Hardware Steering Column & Key
GMC Engine = Hummer Replace Your Monsoon Head Tire Chains Why the cable on the Tcase?
Block Heater Replace Torsen 1 Diff in an ABS Truck? OBD for 96 Gas Trucks OBD Code Database
Bad Vibration & Noise Hummer Turning Radius Duramax Upgrade Cost Warn Winch Remotes
Why is the Roof Steel? Hummer Center of Gravity Shifter Interlock Problem AMG's Hmmwv Policy
Don't Modify Air Intake HMMWV Hub Tie Downs Prevent Rust Fuel Fillers
Front diff Off-Center ? Windshield Wipers Cool Sun Roof Idea Rear Defroster for Hardtops
Dip Stick Length H1 Exhaust Unlike Hmmwv Window Squeak Need More Heat?
Wagon Roof Load Fuel Gauges Odor Removal Door Lock Stems
Folding Windshield? Deep Water Fording Test Slantbacks Shock Covers
Old gossip GM Hummer Dealership Design    

Where did the Name Humvee Come From?

The HUMMER's name originated with AM General for its entry into the US Government's High Mobility Multi-purpose Wheeled Vehicle (HMMWV) development program.  In military circles in the very early 80s, they began to phonically pronounce HMMWV as "HumVee". Soon after HumVee turned into Hummer.

Why is the Front Differential Mounted off-center

To find the reason why in the "first place" one has to go back to  the HMMWV/HUMMER design around 1980.  Originally the design used  a straight front drive shaft running directly from the NPG/NVG model  218 T-case to the front differential.  There was no way to connect a  straight drive shaft without moving the front diff. mounting to the LEFT and  setting the Engine/Trans./T-Case assembly in at a slight angle to the  RIGHT.  Once the 2-piece front drive shaft came into being, they didn't go  back and straighten everything up. 

Why does the Hummer Exhaust Exit out the Rear by the Bumper Unlike the Wheel Well Like the Humvee's?

To lower decibel readings (from the left side of the vehicle) during  by-pass testing to meet more stringent medium duty truck EPA Noise  Emissions.

Deep Water Fording HMMWV

Hmmwv Deep Water FordingThe DWF EXHAUST EXTENSION is not absolutely necessary for the HMMWV with all the other DWF Kit components properly installed &  functioning to do water fording depths up to 60."  It is there  primarily due to the way the DWF validation (test) procedure for  the HMMWV was written.  It went something like this; Must be able to enter water to a depth of 60"...idle for 1 minute ...shutdown  engine for 1 minute... restart engine and idle for 1 minute...and continue through test course.

Why Do Hmmwv Windshields Fold Down?

When the M106 Recoilless Rifle was first test fired directly over  the front of a HMMWV at zero elevation the muzzle blast wiped out both  windshield glass.  AMG went to work and designed a "storage provision"  behind the bulkhead where the entire windshield assembly could be removed  and stored when M106's are mounted on HMMWV's.
BUT ...long before the M106 was mated to some HMMWV's (HUMVEE's) AMG had  designed their HMMWV version to meet the Government's original HMMWV  requirement for "Cube Reduction," which include "height reduction"  for the basic M998 model of the M998 Series.  On AMG's HMMWV  design, they made the B-pillar"removable," the windshield  assembly "fold-down" and even slotted the upper steering column mount so it  could be tilted downward.  The highest part of a HMMWV then becomes  the top of the steering wheel.
The primary reasons for that Gov. requirement was to allow; bi-level  rail car shipping; facilitate crating (Knockdown) for certain shipping  methods; long term (Level A) warehouse storage where HMMWV's are often  placed on racks and the racks stacked 4 or more high.

Dip Stick Length

My 98 turbo diesel oil dipstick has the following dimensions:
Total length to top of handle: 71cm
Total active length of dipstick: 67cm
This is from the bottom to the top, inside the short tube section of the handle, where the handle bottoms out when fitted.
From the bottom, the "add" mark is at 44mm and the "operating range" mark is at 61mm

Door Lock Stems

The door lock stems may be left handed threads.

Odor Removal

Medo's Odor Gun.  It's tops in removing the smell, and Motor Trend did a review of it (long time ago) and rated it highly.  I used it on a Ford Probe who's previous owner was a heavy smoker.  Sprayed the entire cabin liberally (including soaking the vents and the vent tubes) with Odor Gun, let it dry (in Phoenix during the summer, that was pretty quick!), and the tobacco smell went away in a few hours.

For mildew removal and some odor removal - BG FrigiFresh.  It's an industrial spray chemical that A/C tech's use to remove mold and mildew, and removes the smell as well.  I found out about it when Toyota Motor Corporation used it when they did a huge press junket in Hawaii for the Toyota Tundra from 1998 to 1999 and the A/C tech's talked about it on one of the Toyota boards.  

To use the BG FrigiFresh in our trucks - do this:

1) Check and clear the A/C drain tube.
2) Turn the A/C vent on High (non-recirculation).
3) Spray the BG Frigifresh into the cabin air intake (passenger side front, between the door and the air cleaner).  Repeat as necessary.  Let the product dry out and vent thoroughly before using the A/C! 

To use the Odor Gun - spray liberally into all vents.  Let it dry before using the A/C.

Odor Gun's also hard to find as well.  You can get it here:

Why Can't I replace the fuel gauges with a standard 90-0 ohm unit? That's what  GM, Stewart-warner, VDO, etc. utilize. not in respect to ohms, but in respect to gauge  dampening.  The situation with HUMMER (H1) fuel gauges in the  early years was the damping effect...none at all, too little or too  much!  The '92/'93 fuel gauges have virtually no damping other  words...accelerate quickly and the needle does not read actual fuel  level...decelerate quickly and again the gauge reading is not  accurate.  In '94 model year there was a concerted effort to 'dampen' that  effect.  Unfortunately it took several years before they zero'ed in on just  the right amount of damping.  So replacing a ...say 1998 or so... fuel  gauge with a non-H1 fuel gauge could mean starting that trial  & error process all over again.

Window Squeak?

In my truck, some time ago, I got some water between the glass and the rubber gasket.  It squeaked badly for several weeks. It went away after I parked my truck in the hot sun for several hours a day for a couple days.

Wagon Roof Load Design

The Wagon roof was designed some 5 years before AMG even  thought about carrying a load on top of it like an accessory "Roof Rack."   The feeling was not to go back and re-design the Wagon roof/support  structure just for an "accessory" so engineering simply imposed a 300  lb. payload limit in addition to the weight of the rack itself.
It's not that AMG's roof rack for the Wagon can't hold more than 300  lbs., it is the Wagon ROOF itself aft of the C-pillar (supported ONLY by sheet  metal) that could pose a problem if severely overloaded. The tell-tale  signs of a Wagon roof rack that has been severely overloaded are  typically:

  • Cracks in the paint along roof panel seams and possibly cracks in  the panel sealer.
  • Sheet metal bowed inward or outward at diagonally opposite  corners at each rear side window opening.

Rear defroster on my '94 hard top

If the last six of the VIN on your 1994 HMC4 are 159405 or higher.  Any competent HUMMER H1 dealer should be  able to quickly dig up the 4 component part numbers that make up the Rear Window  Defroster "Kit" for you.  As I recall, AMG also offered Rear Window  Defroster "Kits" for sliding and stationary rear windows on 2 Dr. and 4 Dr. Hard  Tops as well as you lucky Wagon Owners with the Lift gate/Tailgate  combination.

Mojave Heater

I just installed a Mojave heater by Flex O lite and it ROCKS! I put a couple of metal tubes through the bulkhead and installed the heater under the dog house on my '92 LE. If you need extra heat for your Hmmwv this would be a good choice.

Windshield Wipers and Squirters

My windshield wipers don't seem to be doing the trick in the winter with all the salt, and frankly a rain storm in the summer is not picnic either. They don't work and chatter. I have replaced the blades, it helps a little.

New arms and squirters were introduced around 2000. I've found them to be vastly improved over the 2 previous design  arms/blades AMG has put on the HUMMER (H1) in every respect except cost!  T
Since we are talking about that general area, Owners of older HUMMERs  may be interested to know there are "adjustable" design windshield  washer nozzles (to replace the "fixed position" black block nozzles)  and inline washer fluid check valves available for upgrading.

AMG p/n 6012641 Arm, wiper (2 required)
AMG p/n 6012642 Blade, wiper (2 required*)
AMG p/n 6006600 Nozzle, washer (2 required)
AMG p/n 6010771 Valve, check-washer fluid (2 required)
OEM wiper blades are: ANCO 91-12 (2 required) AMG p/n 6012642
Slant-backs, rear wiper blade is ANCO 91-15

Fuel Fillers

The fill pipes with "screw down cap" as you say it, were effective  with Job #1 on the 1995 model year GAS powered HUMMER (H1) and ALL HUMMER H1's  (1996 & up) built with dual fuel tanks.  Those fuel fill pipes  with larger diameter "neck" as used on military and early model years  Civie diesel HUMMERs, gain nothing as far as faster fills.  In fact if the  screen is left in, it may actually take longer to fill.  The reason the  military version has the larger neck was due to a Gov. requirement for the  HMMWV (and other Mil. wheeled vehicles) to accept up to 2" dia. fuel  dispensing nozzles.  As I recall both types are fill rated at  around 10 GPM.

A Cool Waterproof Sun Roof Hatch in Your Hardtop

Look at marine hatches, they are waterproof and have the look

Prevent Rust

Try this rust preventative formulated by Boeing Aircraft Co. : if works quite well and can be removed with brake parts cleaner.

SKYCO OSPHO is used as a primer in many marine and ship applications.

Rust Bullet comes recommended by Hummer owners

Por 15 is a competitor to Rust Bullet and is very good.

HMMWV Hub Tie Down's

On the humvee hubs there are mounts that are usually on all four hubs.  You can remove the airlift/tow shackles from the front and rear and install them on the hubs.  This process is used a parachute air dropping the humvee or in LAPES operations (Low Altitude parachute extraction system).  When air lifting the harness attaches to the front rings in the hood and the rear shackles on the frame or bumper on humvee's equipped with the airlift rear bumper.  But when the humvee is air dropped or use with LAPES these shackles must be moved to the hubs, so that when the vehicle is securely tied down on the drop platform the suspension is still uncompressed and can absorb some of the impact.  I say some because the prep setup involves quite a bit of rigging with dunnage and corrugated cardboard material which is placed under the humvee and is crushed upon impact as the suspension compresses.  After landing, assuming it went well the crew has to remove all the drop stuff from the truck, and take the shackles from the hubs and replace them on the front and rear.  On a CTIS vehicle(rare) there is more labor involved in the drop setup.  These brackets are NOT used for some kind of extraction setup like the old hub mounted capstan winches that were sold years ago. 

Is There a Higher Incidence of Maintenance Problems These Days? (Nov 16, 2003)

1.) Let's face it; Hummers are always having problems but now many trucks are out of factory warranty and have even run their course of extended warranty. This means that many more owners are bearing the high cost of maintaining a Hummer. This alone is a real motivator to educate yourself about maintenance problems. Face it, when your truck is under warranty you really don't care what it takes to fix as long as it gets fixed. Because you're not paying you don't have a vested interest beyond curiosity.  I know
many of the dealer mechanics who just keep changing parts out until the problem is solved.  This is fine as long as you're not the one paying or have very deep pockets.  That's why we find ourselves answering questions so owners can be informed when they take the truck in for service.

2.) The fleet of Hummers on the street is getting older and will as any machine have an increasing need for repair.

3.) Because many of the trucks have sold used at very low prices many of the new owners don't have deep pockets.

4.) Why the high incidence of problems in the last two months?  I've found that whenever the seasons change from hot to cold or cold to hot outdoor equipment seems to start breaking down.  I used to own a bunch of outdoor quarter carwashes located in IL.  About this time of year I would have problems with the bill changers, vacuum cleaner motors would burn out and timers would go bad.

5.) Do the diesel powered H1's have more problems then the gas trucks. In my opinion the number of gas trucks is too small to make a significant comparison.

How Much do Hummer's Cost?

'92 4-Passenger Wagon base MSRP $47,600
'93 4-Passenger Wagon base MSRP $52,950
'94 4-Passenger Wagon base MSRP $55,089
'95 4-Passenger Wagon base MSRP $58,419
'96 4-Passenger Wagon base MSRP $61,387 (add $4307 for turbo)
'97 4-Passenger Wagon base MSRP $66,321 (add $4523 for turbo)
'97-2 4-Passenger Wagon base MSRP $67,885 (add $4523 for turbo)
'98 4-Passenger Wagon base MSRP $72,309 (add $4613 for turbo)
'99 4-Passenger Wagon base MSRP $82,421 (Turbo standard)
'99 (mid year price increase) 4-Passenger Wagon base MSRP $85,718
'00 4-Passenger Wagon base MSRP $89,410
'00 (mid year price increase) 4-Passenger Wagon base MSRP $92,539
'01 4-Passenger Wagon base MSRP $94,529
'02 4-Passenger Wagon base MSRP $112,949 (Many options made standard)
'03 4-Passenger Wagon base MSRP $116,483 (1st 12 scheduled services included).
'04 4-Passenger Wagon base MSRP $117,508 (Leather now standard).

What's the Mileage?

You will get 9 to 15 with a Turbo diesel. Tires make a lot of difference. On a road trip my wagon with MTR's got 11 to 12 and another wagon with GSA's got 13 to 14. We kept the speed under 65 mph. Go down to 60 and you can get 15. Around the city in the winter (Chicago Area) I get 9 to 10. A gas truck (95 or 96) will get 7 to 11 mpg.

New Dealership Design

How Many Hummers are there? (March 2003)

For the record: Arnold S. did get "Limited Edition" numbers 0001 and 0002,  but they were hardly the FIRST civilian models in existence.  The first 15 (1992 model year) civilian HUMMERs off the assembly line all  went to Coca Cola and its CEO at that time. AMG did "LEASE"  to Arnold S. two modified military HMMWV's; one he got in July 1991 (a 686  CARC Tan slantback) and the other in Sept. 1991 (a 35% gloss Tan similar in  looks to a 4 DR. HDTP). 

AM General referred to this one as a "Limited Edition" and was sold from AM General to the Buyer Dealer network was in place at that time.  The VIN number indicates it is a 1992 model year and was assigned "Limited Edition No. 0124."  The 124 may or may not represent the 124th civilian HUMMER (H1) off the line as some Buyers were able to pick and choose the "LE Number" they
wanted.  Brush and Headlight Guards were available factory installed "accessories" way back then.

Arnold's '92 Limited Edition  "WAGON" would have been VIN 132141 I recall.   It very well could have been 'billed' as "the first 92 Civi 'WAGON' in  existence" ..but definitely, positively, absolutely it was not the "first  92 Civi HUMMER in existence." 
FYI: 1992 models in order they first came off the production line  were; 2 DR HDTP immediately followed by the 4 DR HDTP, a month or so later  came the OPEN TOP and last about a month later came the WAGON.

The term "Desert Storm Edition" was coined by a few of the media in articles of that period..most likely to draw the link between Mil. HMMWV's in Desert Storm to the then new Civie HUMMERs offered to the general public. 

How high did the VIN numbers go for the 92 model.
Would you believe NE136616?

My 93, 134642,  which was originally painted desert tan from AMG was produced 11-92 and sold and titled as a 93 on the dealers lot. Just does not sound right, does it??? 
..until you consider this:
1992 model year HUMMER production (including Limited Edition) began in June 1992 and the build was completed in December 1992.  The 1993 model year HUMMER began production in August 1992, so there were 5 months that 1992's and 1993's were built concurrently on the very same assembly line.

Question! I'm the very recent owner of NE130420.  I can't find any other proof  that this is a limited edition like the name plate under the steering column etc. but it certainly looks like a Desert Storm Edition?
The reason you cannot find other proof as you phrased it, may well be that NE130420 was NOT a Limited Edition per se.  Of course only AM General will be able to confirm it one way or the other for you.  If it turns out yours is not a LE, AMG may share with you what SPECIAL PURPOSE NE130420 was used for.  Other Special Purposes 1992 HUMMERs were used for included; Coca Cola/Mellow Yellow giveaway, Neiman Marcus, Engineering Homologation, Show/ Promo/ Media, Dealer Development, Special Equipment Applications, V.I.P.

The last six (6) digits of a 1992 LE HUMMER's VIN were never intended to reflect the Limited Edition name plate number assigned that vehicle. Therefore, there would not have been a direct number correlation with say, NE130249 and a Limited Edition No. 0249.  An exception may be IF the Purchaser requested AMG to assign a specific number to the LE name plate for his/her HUMMER.  An example of those who requested a special LE number would be Terry & Lynn from American Hummer.  They requested and got Limited Edition No. 1000 although only 299, 1992 HUMMERs came off the assembly line built specially for the "Limited Edition" program.

So all in all it is possible you may not own a '92 HMC4 "LE" Desert Storm Edition, but rather a '92 HMC4 "SP" Desert Storm Edition!!!

The four models offered in the 1994 model year totaled 718.  A somewhat educated guess would put the Wagon model build around 45% or 323 units.

There were 945 H1's built in the 1998 model year. As for break-down by model, color, etc. AM General has that tucked away in their production data base.

There are around 11,700 H1's ever built (1992-2006). To put that in some perspective, Rolls Royce built TWICE as many Rolls over that same period as AMG did H1's. Yet another way to look at it; this year there will likely be around 1,000 H1's and 40,000 H2's rolling off AM General's assembly lines.

There was a grand total of 618 H1 Gas powered trucks produced in 11 years.

1,432 for the 1995 model year

1,374 for the 1996 model year

Since 1984 about 150,000 Military HMMWV/HUMVEE's have been built in dozens of different variants/models/configurations for U.S. and many foreign military customers. (written in 2003)

H1 production for '03 was around 365 plus 112 for the border patrol.  763 was the sales total reported in Automotive News in the January 12th issue. The sales number  included leftover '00s, '01s, and '02s as well as '03s reported sold during the year.

Total accumulated production as of the calendar year 2003
HMMWV's: 171,824
Hummers (including commercial/industrial): 10,877
H2's 62,214

1992 316
1993 612
1994 718
1995 1432
1996 1374
1997 1208
1998 945
1999 831
2000 1332
2001 869
2002 703 H1 deliveries:  730
2003 477 H1 Deliveries: 720
2004 194
2005 Skipped model year
2006 691

There were 65 Anniversary models in 2002.

There were 39 slantbacks in 2000

The slantbacks were designed for HMMWV's with rocket launchers so the exhaust and blowback from the launch wouldn't burn the rear of the truck.

AMG copied the slantback design from CalGold and they sued. They also had a leaking gasket around the lid. There were actually 41 made; that number included 2 engineering prototypes. After the 39, the rest were converted back to wagons (they were in various stages of completion). The 39 built were retro-fitted so they would not leak; although some had problems anyway. Rumor had it the last 2000 Slantback (a Red one) at AMG was actually converted to a 4 DR. HDTP for a customer before it left AMG. 

It's only the last 6 digits of an AMG Commercial (Civilian) HUMMER H1  "Vehicle Identification Number" - (VIN) and the last 6 digits of an  AMG Military HMMWV (HUMVEE) "Serial Number" that run  sequentially.  And forget about GM's H2, H3, H?...a completely  different ball game in this respect!!!
On April 13th, 1984 when the first production HMMWV rolled off the assembly  line at the AM General Plant in Mishawaka, Indiana.  It was "Serial Number"  M998-000001 ...and AMG's sequential vehicle numbering system was off  and running.
Serial Numbers 000001 thru 072546 came off the assembly line as Military  type HMMWV's (HUMVEE) although a handful were reconfigured at AMG's Engineering  Headquarters in Michigan to something between a true production HMMWV  (HUMVEE) and a true production Commercial (Civilian) HUMMER. 

Only  15 HUMMERs (H1) were built from June 1, 1992 through July 10,  1992.  They were HMC2 and HMC4 for Coca-Cola/Mellow Yellow HUMMER  give-away contest and for a Coca-Cola V.I.P. 

Hummer History - UPC/ Model codes i.e. HMCO

R=Recruit series; original designator for a "Recruit Series" on announcement day, May 25, 1993.
The Recruit was only available May 12 to at least November 15, 1993. They were available as 2-door and open-top models only.  Starting price was $39,500.  (The brochure has a couple pictures of a tan 2-door as well.) No rocker panel protection, no drive line protection, no winch, no spare tire, no power mirrors or windows or door locks. "Durable, Easy Maintenance Trim" and "High Back Cloth Bucket Seats" are among the listed standard equipment.

"Sportsman  Series" HUMMER" for under $49K.  As it turned out the Dealership body  turned down
the "Sportsman" at the 1998 dealer meeting and only 1 was built.

VL=Value Leader; began using this designator for Recruit Series 2-Dr. & Open Top very shortly after announcement day. "VL" was also used in 1994-1996 Model Years to simply designate the "Base Model" 2-Dr. & Open Top.

HM=HUMMER; at one point AMG called all variants of their HMMWV design vehicles, HUMMERs

C=Commercial; sometimes referred to as the "Civilian Version."

F=Fleet/Industrial; sometime referred to as the "Commercial Version."

4=4-side doors

2=2-side doors

S=Station Wagon; most often simply called the "Wagon." Early Model Years had a rear lift gate and a tailgate. Later Model Years had two rear Vertical Doors, sometimes referred to as "Barn" or "Swing-out" doors. This would be a HMCS.

SB=Slant-Back; 4 (side) doors plus one rear Slant-Back (hatch) door.

O=Open Top/Body; sometimes referred to as "Soft Top." When an "L" preceded the letters "CO" in the model code, the side doors were termed "Soft" meaning; metal and vinyl construction. When an "M" preceded the letters " CO" in the model code, the side doors were termed "Hard" meaning; all metal frame construction.

X=Enlarged 2-Dr. cab - 6" longer. Sometimes referred to as "Extended Cab."

On Board Diagnostic Versions

ALL Gas trucks are OBD1. Little known fact; ALL '96 HUMMER Gas engines were GM (LO5) 5.7L versions actually "built" in 1995. So when looking up engine spec 's for a '96 Gasser, just lookup '95 Medium Duty GM 5.7L LO5 engine data.

All Turbo-Diesels are OBDII.

Engine Analyzers:

I ended up owning the OTC/SPX Techmate I, GM 16/12 pin NON-OBD II DLC (data link connector) adapter (#02001575) and OBD II conversion kit for my 95 Gas truck.

The OBD II kit is required for all the other trucks we work on (some 1996 and all the newer ones).

1996 was a year of change so you may have either one of these setups. In 1996, the DLC connector looks the same for both OBD types. This required a special adapter to the pre-OBD II meter.

The OBD II chip manufactured by Vetronix for SPX for AMG will allow a Tech OBD II meter to read all codes, (universal and AMG specific) turn on and off sensors and advance timing. A meter without this specific chip can only read codes.

You'll need a Vetronx Tech2 to do the reprogram, if I recall correctly.  Again, if my memory works, you'll also need the Vetronix Service Programming System (SPS) and/or the Tech2 Pro option to do the programming work.

Vetronix in Santa Barbara, 1-800-321-4889 is the actual manufacturer of the OTC/SPX product.

Before you get your new pcm there is a program issue you should check first. 99 and newer hummers have a program in the pcms for the glow plug feed back circuit. if you put one of these in your vehicle the check engine light will come on. The new pcm's are not reprogramable for a 96-98.

An interesting Product called the CarChip

It is a OBDII scanner and can read (and clear) the trouble codes for your vehicle.  It also monitors your vehicle for the last N number of hours (depending on which you get).  It can monitor 23 possible engine parameters recorded every 5-60 seconds.  Including (from the brochure) RMP, throttle
position, fuel pressure, battery voltage, etc.

You just plug it in and leave it (it is a small module) then you pull it out periodically and use the USB port to hook it to your computer.

Anyway, I thought it looked pretty cool and it looks like it will be a better deal than a $300-$400 scanner and do more too.

The link is:

Transfer Cases Changes

Some time during the 1994 year there were internal changes to the t-case. The main shaft is different, with different diameter and splines where the rear drive shaft fits. They are not interchangeable, nor is the rear drive shaft front section.

The spline dia. increase went into effect with 1995 Gas Job #1, and was a running change for the 1995 diesel. The larger dia. (& capacity) splined shaft was required due to the higher "spike torque" of the gas engine. Under certain conditions, the Gassers would actually twist the splines inside the smaller rear prop.

I have seen several '94 trucks with the newer style t-case in it probably due to field replacements.

The 1995-2000 T-Case can be used in a 1994 with an easy change out of the rear prop shaft from p/n 6002594 to p/n 6003666. Some simply changed out the slip yoke to p/n 5743957 and used the remainder of their original 1994 rear prop although that would make the overall length approx. 1/2 inch longer than the new prop shaft.

Late in 1997 for VIN #176780 and later the transfer case pinion gears were hardened.

Dual Locking Gas Caps

NAPA (BALKAMP) caps # 703-1597
(non-venting type, keyed alike). $14.49 ea.

Duel Locking (keyed alike ) diesel caps/ gas cap from Stant Part # 17596. You can buy these direct from Stant using a MasterCard or Visa. Your cost is $16.04 each plus there is a $5.00 per order shipping and handling charge. Your total for two is $37.08. Contact Stant customer service at 800-822-3121 extension 330 to place your order

All '95 & '96 Gassers & all Diesel HUMMER H1s '96  & up use the same type of NON-VENTING fuel caps.
Technically, ALL HMMWV and '92 thru '95 HUMMER H1s Diesels use NON-VENTING  fuel caps too, but of a completely different design.

Diesel Fuel Additive

The only thing I use is Stanadyne Performance Formula. I use it when it gets colder then 20 degrees f. and occasionally in the summer to lubricate the injection pump. I'll also use it if I'm going to do some wheeling in high altitudes because it gives me better performance. The stuff is really good. You will be able to tell its there a few minutes after you add it. The engine starts right up, smoothes right out and quiets down.

How to Tell a 97 from a 97.5

VIN 176477 and later, commonly referred to as "97.5"
Redesigned HVAC by ACME (much better)
Monsoon Stereo by AC Delco available
Constant tension (spring type) clamps on transmission and T-case cooler hoses

VIN 176780 and later
Hardened transfer case pinion gears

Unknown point
added a switch for the cargo-area light that turns the light on when you open the wagon ambulance doors

The Myth of Diesel Engine Braking

I always thought since a diesel has such high compression it's ability to brake would be phenomenally better then a gas engine. This is not the case and here's why. A gas engine has more engine braking than a comparable displacement diesel because at low throttle levels a gas engine is working against a closed throttle plate. A diesel has a wide open intake manifold without a throttle plate. Think of a diesel piston and cylinder like an air cylinder. If you press the piston up to near TDC (top dead center) with the valves closed, it takes a lot of pressure, right? But guess what, after rotating beyond TDC all that compressed air now pushes down on the piston to accelerate it to BDC (bottom dead center). A gas engine will generate about 25" of vacuum with the throttle closed, so when the piston comes up to TDC, very little pressure is there to push the piston on the down stroke. Then, when it wants to pull in a fresh charge, the engine has to pull against the vacuum. All this consumes energy and creates what is termed "compression braking".

Of course, a diesel does produce some compression braking due to mechanical losses and heat generation, but a similar displacement gas engine will always generate more "compression" braking.

Protect Your Truck From Brush Scratches aka Pin Striping

Here are some links for the adhesive "pin striping" protection I believe the primary product is one called ScotchCal trademarked by 3M and used for rock and chip protection on the front and rocker panels of some new cars

I came across this interesting little product called "Snake Skin". What you do is roll on this Total Coat Snake Skin, let it dry, and it's supposed to protect the vehicle finish for about 6 weeks.

Need Interior Vinyl?

Try, they are the one's who make the Hummer interior for the most part.

Repairing Roof Seam Rust / Leaks

The roof joint is sealed with body seam sealer which is a special 3M product. When it gets old it looses its flexibility and cracks along with the paint causing rust and leaking.

Dig out the old sealer in the crack and clean it out good. A small air powered wire wheel is used. If there is still rust in the groove you mask off the crack with 2 layers of duct tape, cover the whole truck with plastic and sand blast out the crack. Then it is feather edged. Then it is painted with primer, then sealed with 3M Body Seam Sealer which is paintable. Then the entire crack is feathered again as needed, and either spot refinished or the whole roof panel is refinished with either single or 2 stage polyurethane paint . (Spies Hecker or Standox, which are DuPont now)

Brake Fluid

ABS equipped trucks must use DOT-3 or DOT-4 fluid. Using DOT-5 is dangerous when the ABS system is installed.

The military specification for DOT-5 said that if DOT-5 was inadvertently mixed with DOT-3 or DOT-4, that it should cause no harm, either to the system or the performance in the short run.

Why DOT-5?

DOT-3 and DOT-4 are made with chemicals that are related to anti-freeze. We know how well anti-freeze mixes with water. Despite their appearance, there is NO oil in these fluids. They are hydroscopic (absorb water) which creates problems for vehicles that are stored for extended periods such as Hmmwv's. DOT-3/4 doesn't like mixing with air, and won't readily form bubbles.

DOT-5 is not based on the same chemistry, and is much closer to oil than the other fluids. DOT-5 is silicone based and doesn't mix with water. This allows water to 'fall' or settle to the lowest parts of the system, where it can cause as little damage as possible during storage. DOT-5 will mix with air, or if sufficiently agitated form bubbles without air. This is why it doesn't work well with anti-lock brakes; the ABS controller causes bubbles to form in the DOT-5 fluid.

Side note: Do not bleed brakes using a vacuum system if you have a truck that uses DOT-5 because it causes bubbles to form. Also when bleeding brakes with DOT-5, care must be taken when pouring it into the master cylinder to avoid forming bubbles .

Non-Standard Paint Color

If there is a reason to suspect your H1's paint color is NOT one of those factory offered for that model year, check the interior surface of the driver's side B-pillar for presence of a special paint code tag. In some cases it may be necessary to remove one or more of the B-pillar trim panels to see it.

Dash Pad Trim Grommets

Hummer Dash pad grommetsThese parts were first used sometime around 1999/ 2000 to give a nice finished look for the cracking plastic screw holes on the dash crash pad (the long pad that runs on the top of the dash next to the windshield). If you want a nice inexpensive way to cleanup the look of your pre 2000 truck pickup 7 of these Gray "Grommets" AMG p/n 6010765G costs about $2. ea. and the 1" long gray trim screws, p/n 6002686G cost about 40 cents ea

Hummer Crawl Ratio / Gearing

What is the actual gear ratio of a Hummer when you take all the gear boxes into account? If you have a 2.73 ring & pinion gear in your differential (pre 1998) it would be equal to 5.24 on a normal vehicle because you have the geared hub which is 1.9:1. Most newer Hummers use 2.56 ring & pinions which is effectively 4.92 to 1.

Crawl ratios are calculated by multiplying (Trans 1st gear) x (Trans Case Low) x (Diff Gears) x (Hub Reduction), which works out to 33.16:1 or 35.35:1 depending on which differential gears you have.

Canadian Daytime Running Lights

This is what AM General added to a 1998 HUMMER H1 to meet the Canadian requirements for Daytime Running Lights (DRL):

Qty. 1 AMG p/n 6002919 Jumper-DRL
Qty. 1 AMG p/n 6002626 Harness-DRL
Qty. 1 AMG p/n 6002625 Module-DRL (no longer available)

The 3 parts should run around $100. USD

Link to info on importing a truck into Canada

CTIS Leaks

The problem is the front and or rear tires loose between 3psi to all their air. You will find that when the trucks sits overnight you have to re inflate the tires. I found that the lines start to leak when the season changes. Every fall when it starts to get colder either the quick disconnect or one of the plastic line fittings begins to leak. 99% of the leaks are the quick disconnects.

The first thing I do is disconnect the quick disconnect on both rear wheels and see if the system holds air. If it does then I know the leak is in the cti lines on one of the rear tires or a rear tire has a leak. Do the same and isolate the front. Then spray down the air lines with soapy water and look for bubbles.

If the above doesn't work go under the truck and spray down all the air lines and fittings with soap water to find the leak. Don't forget to check the valves under the hood.

The next most likely place would be the Hub Spindle Seals. To check them, see if air is escaping from the hub vent lines. With tires connected to supply pressure, disconnect the vent line from the hub. Connect a short piece of hose to the vent fitting and hold the
loose end under water in a cup and look for bubbles.

CTI Pump Rubber Mounting Vibration Isolator

CTI Pump Rubber Mounting Vibration Isolator

WW Grainger and bought part number 5XK72 replacements for $1.55 each.

Grainger Website

CTI Hose Leaking Entering the Front Hub

I have been loosing pressure in my front tires. I had them broken down and re-sealed, but they still leak. I noticed as hissing sound, and found it coming from the CTIS lines just before they enter the geared hub on my front driver side wheel. What do I do??

You must not have been the only one to experience that condition.  A few years back a 45 degree fitting (AMG p/n 4-4-140339S $17.00) was released to address this condition.  Your leak may have been the result of straining the braided hose at the swivel fitting during full right or left turns.  There's probably not much that can now be done for that leaking hose.  When you replace it with a new stock one, you may want to consider adding that new 45 degree fitting before connecting it at the geared hub end.

Snow Plow For your Hummer

I've been messing with snow plows specifically for Hummers (H1) applications back as far as 1992. That by no means makes me the "expert," it only means I've had an opportunity to see many snow plows on H1's.

The only AM General engineering approved snow plow was (is?) the bolt-on kit
designed by Meyer specifically for the Hummer (H1). No cutting or welding
required and was within the H1's front axle gross weight rating. Your 1994
4DR HDTP front axle curb weight (3,265 lbs.) is already within 800 lbs. or so
of the maximum weight of 4,100 lbs.

The snow plow prep-package front springs are a must-have when mounting a snow
plow on 10,300 lb. GVWR H1's.

I'd consider the Warn OEM winch out of the question with a snow plow not only for its own weight, but it can also move much of the plow weight 6 inches further forward of the front axle centerline.

What is the Normal Oil Pressure for my Hummer?

Up to 1996 - 10 PSI idle and 40-45 at 2000 RPM.
January 1997 to March 1997 NA, and all turbo engines from January 1997 - 6 PSI hot idle, 30 PSI at 2000 RPM (due to oil cooled pistons)
April 1997 and later NA - slightly higher than turbo engines (due to oil cooled pistons in cylinders 3, 4, 7, and 8.)

An early NA engine that shows only 6 PSI (idle) will probably be OK, but that does indicate either excessive wear, usually crank bearings, a problem with the oil pressure regulator, or possibly a clogged cooling line or cooler.

A general rule of thumb (for all engines) is 1 PSI of pressure for every 100 RPM, or better.

Rapid Release Pins also known as Quick Release Pins or Ball Lock Pins

Quick Release PinsWhere can I get the pins that go in the factory push bar? I would like to know the exact dimension for the 4 pins that attach the bench seat to the seat frame.

This company sells a wide variety of lanyard pins.  Just take measurements of what you want and save money by using them.

Pin length: 5.050"
Pin diameter: .497"
Shaft length: 4.504"
The distance between the ball and the shoulder?  (i.e. the "usable" length) is .495".

Turn Signal Flasher with LED's

Again - anytime you change to anything LED from a turn signal standpoint you need to change your flashers to a Variable Load thermal or electronic flasher.  Either a 552 or an EL12 will work fine.  I use a 552 for my hazards and an EL12 for my turn signals.

6.5 Turbo Diesel Engine used in GMC

The version we have in the Hummer is a "G" type or GMC/Chevy Van application. The Hummer engine just like the van locates the rear of the engine in the passenger compartment unlike a firewall separated engine bay in a standard GM pick up. The primary difference from the standard GM pick up motor is the intake , exhaust and turbo used in the Hummer. The Hummer uses the same turbo setup as the van.

AMG  picked the 6.2 engine for the HMMWV program because it was already used in  other vehicles and this would reduce parts and simplify maintenance. Since the  6.5 is based on the 6.2 I'd assume AMG picked it to keep costs down and keep  things simple.

Where to Get Rivets and Nut-Serts

Jay-Cee Sales and Rivet Inc, 32861 Chesley Drive, Farmington, MI 48336,

This is a huge distributor of Nut-Serts, Rivets, etc.  They primarily sell to large corporations but have sold to walk in customers as well.

The minimum order is around $15.00.  They carry all different diameter and length Nut-Serts.  I bought Nut-Serts for 3/8 inch diameter bolts coarse thread, around 3/4 inch long un-collapsed, about 1/2 inch long collapsed, around 100 pieces for $15.00.  They have steel, aluminum and all other types of fasteners that fill a several hundred page catalogue.

Hummer Steering Column & Key Replacement

The Hummer uses a early 80's Ford LTD2 steering column which may have many of the same parts as a Ford Escort. That's why Hummer's have a Ford ignition key. The Hummer is a one key vehicle meaning that one key opens the doors and works the ignition. The Hummer uses a Ford key replacement code #23.

Replacement Block Heater

All Hummer diesel engines come with a block heater. If yours goes out you can get a new block heater and cord for $19.95 at a local parts store (telling them I had a '97 6.5 GM TD). The one I found was made by Five Star Manufacturing Co. they call it a Frost Plug  part # 10612 market under the name KAT'S heaters.

Where is the Center of Gravity of a Hummer?

The center of gravity, CG-X (X=horizontal) of a standard  T-diesel Wagon WO/Winch at curb weight is 65 inches to the rear of the  vertical centerline of the front axle. Front-to-rear, the balance point is within a few inches of the key hole in the driver's door for all models unloaded.

Replace Your Monsoon Head

All I wanted to do was replace the Monsoon head unit in my 98 wagon and keep the existing Monsoon amp, speakers and sub which means finding a way to wire an aftermarket radio into the Monsoon system.   Aside from the new radio, it costs about $20 for the two connectors to make it happen.  The Monsoon head unit uses a standard GM radio connector on pre 2001 trucks. On later models (2001) they use a standard VW/ DIN connector. The amp is fed by the line level outputs from the head unit. The Monsoon power amp is setup to take speaker level inputs so you can feed it using the output from almost any head unit whether it has line outputs or not. The Monsoon power amp automatically turns on when it senses audio input so you don't have to worry about turning it on. '99 and newer Monsoons have auxiliary inputs on the back of the stereo.  You'll need to splice into the right wires to use them.

I purchased the Metra GM 21 pin wiring harness from Circuit City for around $15.  The part # is 80-1858.  You can order it from   Metra converts the factory connector to a universal connector so all you have to do is buy a Metra connector for the new radio you want to install.  In my case it was a Sony head unit so I purchased Metra part # SY1680 for $5.

The security tool that comes with the Sony fits the Monsoon head unit perfectly.  If you aren't lucky enough to get a new head unit with a security tool that will work on the Monsoon, you can very easily make one.  The way the Monsoon security tabs release is by shoving a thin piece of metal in about two inches.  Once you feel resistance it's only about a quarter inch more to release the radio.  If you look at the slots on the front of the Monsoon you can see how wide to cut an improvised tool. Anything thin and stiff will work.  Hanging folder metal strips, an old CD, a credit card, etc.  Just cut it to fit in the slot and push it in.  You'll need two because you have to release both sides at once.  With the tools inserted just grab the head unit and yank it out.

The antenna connection on the Monsoon head unit is a standard sized connector so you don't need an antenna adapter for a new head unit like with most GM's.

On the newer Monsoon there are two plugs I did not use. One seems to be for the Monsoon CD changer and the other is for the Rear Seat Audio Unit

Tire Chains

Unfortunately, these chains are now very hard to get. I received an email from an owner who called Rud. They told him that there were no chains stocked in the US. They wanted 1750.00 / pair with delivery in 10 to 12 weeks.

"I could not recommend the chains until I had tried them. I have now tried them and am very pleased with their performance."

I was trying to climb a slushy, snow-packed trail and had only limited success with the MT tires. They would slip and dig holes, even using BTM. (It was difficult to stand up on this road, too.) Lowering the tire pressure helped only a little. I managed to turn around and go back down to put my chains on. I returned the tires to normal pressure, and mounted the chains on all four tires. BIG DIFFERENCE. Very little slipping, and no BTM necessary. I climbed the trail easily. (Had to turn around later anyway.
Hummer just won't do 6' snow banks. Oh well...)

These chains are manufactured in Germany. I tried every US manufacturer of tire chains. No one made chains like these in a size suitable for the Hummer tires.

They are stocked in the US by Rud Chain, located in Cedar Rapids, Iowa. Phone is 1-800-533-7993. Order chains "90020 with modification for use with Hummers". The cost as of 1/2006 is $320.00 per pair. Realize that over time prices do change. They weigh about 67 lbs per pair.

These are heavy duty truck chains. (The same manufacturer also makes them for dual wheels.) They have a built in tightening system that uses a chain and a cam-type lock to tighten the chains. (No rubber bands to break!)

The modification necessary for the Hummer is to shorten (!) the inside of the chain. Rud did this for me at no charge. They added seven shorter links to the chain, which shortened the inside by about 7 inches. With this modification, the chains fit *perfectly* on my MT tires. If you have larger tires, you could remove some of these links. (The original links were left in place as a safety factor.)

The pattern that these chains make in the show is like this:

  \/ \/ \/ \/
(or like this if the above looks funny on proportional fonts)

- -<>-<>-<>-<>
I would highly recommend these chains to any Hummer owner. The chain pattern provides very good cornering and side-hill traction, and eliminates much of the vibration associated with conventional "H" pattern chains. Installation is no more difficult than other chains, and the tightening system works very well.

Check out:

Rud-Chain, Inc.
P.O. Box 8145
1300 Stoney Point Road S.W.
Cedar Rapids, Iowa 52408-8145

Phone: (800) 553-7993
(319) 390-4040
Fax: (877) 512-7209 (319) 390-3342

Discount tire chains

Safety Cable on Tcase?

Does anyone know why there is a cable bolted to the frame running through a bracket on the transfer case?

The cable is to keep the transfercase from being pushed back into the fuel tank in a crash.

I Hear a Terrible Noise Throughout the Truck

Possibly your 1996 Turbo-Diesel didn't get included in the exhaust system retro-fit that addressed a problem like you are describing.  That retro-fit basically isolated the exhaust system from the frame assembly similar to the design of the 1997 and newer. How do I know if I have the new mounts?

Look at the back bumper exhaust mounting bracket. If it is rather solidly mounted with 2 bolts and grommets instead of suspended by a "p" clamp cushion with the metal bracket sticking thru it, then you still have the early exhaust mounting system. Lots of vibration at idle, in gear. The kit is part number 5744795. The service bulletin is 97-03-01. Be sure and do the whole thing.

Can I Put a Torsen 1 on a Truck with ABS?

The original style Torsen's (Torsen-1's with 4:1 bias) would have a serious tendency to spin the truck around it's axis when the ABS kicked in with one set of wheels on a slippery surface so they had Torsen design a unit that was less sensitive to the kinds of ABS and traction inputs that caused this. That resulted in the Torsen 2 differential. Not only is the bias-ratio lower than the original Torsen's, but  the way it
engages is different. It took them three or four years to redesign the Torsen-2 and ABS system to
keep this from happening. That's what you got in the 2002 trucks with the 3 to 1 bias ratio and updated TT4 system.

It would not appear to be safe to install the original style, 4 to1 ratio, Torsen-1differential carriers and keep TT4/ABS. Also note that pre 97.5 trucks have a different gear ratio.

The Type 1 Torsen's will have the small helical gears (element gears) that are oriented vertically. T2 gears are horizontal.

OBD (on board diagnostics) For 1996 Gas Trucks

1996 was the transitional year.  To make matters worse for you and I and other '96 Gasser Owners, you need to 'trick' the OBD software into thinking our vehicle is a 1995 Chevy Medium Duty Van or something like that..go figure!!!  The 'trick' is in the VIN and Doug H. at AMG should be able to tell you which digits/letters to substitute where.

OBD Code DataBase

The above is a link to a database of diagnostic codes. 

Does a Jeep have a tighter turning radius then a Hummer?

According to the published data the Hummer has a tighter turning radius then a Jeep. The 2005 Jeep Rubicon has a turning radius of 33.5 ft while a Hummer has a turning radius of 25.5 ft.

All HMMWV's/ HUMVEE's/ H1s were designed with the same turning Radius/Diameter.  It's just that the published numbers have been a "little fuzzy" over the years.  Started out publishing 24ft.R./48 ft.Dia., then for a while simply re-stated the Gov.'s original HMMWV spec. requirements. of 25ft.R/ 50ft.Dia., then went to a more consistently achievable 25.5ft.R/ 51ft.Dia., and finally one that covered all tolerance variations; 26.5ft.R/ 53ft.Dia.

I used to have a CJ5 and It was hard to believe that my Hummer has a  turning radius even close.

Here's the problem. In my Hummer Brochures the turning radius is 25.5ft. In the vehicle comparison listings it's 51 ft. which would be the diameter.  My guess is that the people doing these articles never passed high school geometry.  The vehicle listings article give the turning radius 'curb to curb' which would really be diameter. The way to measure it yourself would be to turn the wheel all the way, drive in a circle and measure the radius.

My guess is that the Hummer has a turning radius of 25.5 and the Jeep Rubicon has a turning radius of 16.75.

How Much Does it Cost to Upgrade a Hummer with a Duramax Diesel?

The complete upgrade runs about $45,000 including parts and labor. Not an easy swap if done right.

Jim Lynch, Lynch Hummer

There Are 2 Types of Warn Winch Remote Controls

There were/are 2 different types of HUMMER H1 OEM remote controls used on the 12K capacity 12V. Warn factory installed winch.  Type I was used from 1992 thru early 1999.  They changed configuration of the remote control AND the winch control pack in early 1999. The two types are not interchangeable. I believe you need the Type II remote control for your 2001 H1's factory installed warn
winch.  The correct remote control should be AMG p/n 5939435 and you should be able to order one through a HUMMER Dealers for $85. or less, including shipping. 

Why Did AMG Make the Roof Out of Steel and Not Aluminum Like the Rest of the Truck?

Much, much cheaper to construct..spotwelding steel panels and reinforcements together Vs. riveting and/or welding of aluminum.

Shifter Interlock Is Not Fool Proof

The shifter interlock is a solenoid under the dash connected to the key lock and the shifter. The voltage from the brake light circuit trips it keeping you from shifting unless the brake is pressed.

Not foolproof at all:

Can be forced If the emergency flashers are on, when the flasher cycle is lights on, the interlock is tripped.

Factory Shock Cover

Factory Shock CoverThe shock cover is used by AM General during the frame build up to protect the shock from paint. It is not a service part and is not available outside the assembly plant. The cover will degrade over time and is not a problem. These covers have been found on trucks that are older than 12 years. I recommend tearing them off. They cause dirt and moisture to be trapped in the shock.

AMG's Policy Toward Civilian Use of HMMWV's

Read this Letter

Don't Modify the Air Intake System

Even AMG has not  covered their air cleaner and gearbox vent system interrelated functions  in HUMMER Manuals or as I recall not even during Tech  training sessions, so I cannot hope to cover it properly here ..guess you could  just trust me on this one!
BUT ..basically it all  has to do with the orifice of vent tube, p/n 12340799.  Just where it is located inside the air  cleaner, how it is positioned relative to the direction of air flow, the  velocity of air flowing by its orifice (venturi vacuum effect) that  determines how well, if at all, the vent system functions.  When too  much vacuum was created it actually sucked diesel fuel into the air cleaner on  the original HMMWV design.  For that  reason ever since there has been a separate fuel tank vent line run and it is  always open to atmosphere ..never comes under a vacuum!  If too little vacuum is created or
the  reverse, incoming air pressurizes the vent system, guess you know what the  results can be!