Auburn ECTAD Electric Lockers
Courtesy of Scot Smith - Updated October 26, 2009
An Auburn installed in your diff will cost you about 1450.00.
The kit looks to be pretty complete. It includes, all of the necessary wiring, plenty of connectors, wire ties, loom, fuses, LSD (limited slip differential) additive and the unit itself. The kit does not come with any sort of switch plate or place to mount the switch. The installation instructions are pretty basic and many will likely be left to figure some things out on their own. They could have done a better job on this. The quality of the differential appears to be first rate.
Note: In the summer of 2008 there was a number of Auburn lockers that were not assembled correctly at the factory causing the diff to destroy itself. Read the long story here. Some owners have reported that when the locker is engaged for a long period it may disengage. This may be caused by overheating the electric solenoid. It's probably best to engage the locker when you need it and switch it off when you don't.
The diff is a cone style limited slip and a fairly aggressive one at that. I think that most folks that are used to Torsens and BTMing should be quite pleased with the Auburn’s limited slip capabilities. They have fairly specific lubrication requirements. Use only 80w-90 gear lube (NON-SYNTHETIC) and also require usage of special limited slip additive (included). The instructions say to only use the Auburn additive, but any good LSD additive, like the Ford stuff, will suffice.
The mechanism is actuated by a large electromagnetic coil on the left side of the unit opposite the ring gear. When power is applied, the coil will lock up the unit. I understand that the system can be somewhat sensitive to the quality of the power source, so one should choose a circuit that does not have a heavy load on it. (Don’t wire it in on your stereo circuit or headlights)
Overall, I think the Auburn will be quite comparable to the factory Eatons in function and quality while at a much lower price. The only real difference I see is that the wiring for the Eatons is designed to take instruction from the truck’s computer regarding when it can and can’t be locked (safety type stuff.) None of that will be present with the Auburn unit.
Here is the locker and all of the other pieces of the kit that come with it.
Here is the locker by itself. Looks to be well made and the internal gears look pretty stout compared to the Torsen's.
Ring gear and carrier bearings installed
I drilled the hole for the harness to exit in the same place I always do for the ARB's. This left less slack in the wires than I would have liked to have had. DIY ers should take note here. Drilling the hole where I have marked will give you a little more slack in the wires to play with.
The big fun comes with installing the locker and setting up backlash. Apparently the bearing journals on the Auburn are machined a little differently than the stock Torsen and the Detroit's. The original shims were way too thick to even be able to get the unit into the housing. Even trying the thinnest AMG shims that are available wasn't helpful. We will be supplying a special set of shims with these units and again DIYers need to be aware that a complete backlash setup will be required to install this unit yourself.
Setting up the diff:
I had to use about .055" on the left side and about .095" on the right side. The thinnest AMG shims are in the .070"-.075" range (I don't have the specs in front of me.) Depending on what shims are in your unit, you *may* be able to reuse one of them on the right side. Carrier preload of .008" is a good target to shoot for, however this is not nearly as important as other settings, and having a little less or a fair amount more is not a problem in most cases.
The long story.
Left home late Thursday morning going west to IA to visit the relatives. I was on Highway 34 between Galesburg and Monmouth about 150 miles into the trip. Everything was running well. The tires seems to be running smooth and the engine was purring like the 400 CI engine it is. It was a smooth 4 lane road. I heard a thump that didn't sound good and I asked my daughter if I ran over something. She said, we hit a bump... About a minute later I heard it again and this time I knew it wasn't a bump. I tapped the brakes to disable the cruise control and let is slow down but things just didn't sound right. I could hear something unusual so I pulled onto the shoulder.
I got out and looked under the truck to make sure the drive shafts were there and connected since I have had drive shaft problems before. Both drive shafts were there and connected and all 4 half shafts looked ok. I got back in the truck and put it in drive. Truck would not move and I heard a whirling noise. I thought oh shit, the tranny is out again... I pulled the E brake and put the truck back in drive. I looked under the truck and the front drive shaft was spinning but the front wheels were not. This implied that the front diff was not working. I put the transfer case in High Lock and low and behold, the truck would move. (now being powered by the rear diff only). I got back on the road and only to hear more noises which concerned me greatly that I was going to leave pieces of my drive train all over the road. Now I figure the front diff is toast already but I really don't want it to lock up and take out the transfer case.
I am about 7 miles from the next town. I turned on the emergency flashers and drove the shoulder for into Monmouth and found a parking lot. I got on the phone and made come calls. I managed to contact scot who installed the locker in the diff. He told me that it sounded like the auburn locker came apart inside the diff housing. He told me to pull the cover off and clean out the loose parts and remove the front drive shaft. He also told me that he had a batch of defective auburn lockers about a year ago that were not assembled well that did exactly what mine did. Well guess what, mine was put together about a year ago and sat under the workbench waiting for me to install it. I think there is a lesson in there!
I talked to some locals and they tell me there are two car dealers in town. One is right across the street. I figure I might be able to get some help so I drive over there. The guys are sympathetic but say they cannot help. I manage to persuade them to let me work on the truck in the parking lot but they really don't want me there for liability reasons.
I borrowed a oil drain pan and drained the front diff and I started removing the inspection cover only to discovered the bolts are very tight. A couple were so tight that I broke a socket removing them. I tried borrowing some tools from the garage and that helped and I managed to get all the bolts out except one. I am about 50 miles from my brothers house so I called him up and asked him to bring me a propane torch and some specific tools. While I was waiting for him, I dropped the under carriage protection and removed the front drive shaft. A can of WD40 would have been very useful about now. I lubed the rusty bolts with oil I drained from the diff and reinstalled the under carriage protection. By now my brother had arrived so I tossed the drive shaft and some other parts in the back of his truck. Sadly he did not bring the torch and I was tired and frustrated so I drove a screw driver between the diff cover and the diff housing and pried the cover open enough to get my hand inside. I pulled out 2 gears, some funny washers and a broken shaft. I managed to run my finger into the broken shaft and impale it and draw some blood. I rotated the input shaft and things seemed to turn without making too many odd noises so I bolted the diff cover down.
Since the front brakes mount on the diff I needed to leave the half shafts and the output shafts on the diff to support the rotors. We put in 2 quarts of gear lube and decided it was the best we could do.
We cleaned up our mess and got on the road. I drove to my mom's house without incident. The next day I drove to my bothers house to collect the parts we put in his truck. After leaving there the clutch's in the diff started chattering really bad on turns. I figured this was because I didn't install friction modifier. I stopped at auto zone and picked up some friction modifier and put it in in the parking lot. It helped some but not totally. I managed to drive the truck friday and saturday with out too much problem.
Next day I drove home non-stop. I cruised at 58 MPH all the way back and I didn't want to subject the front diff to faster speeds for fear that it would puke up some more parts. We made it home without incident but the diff was extremely unhappy in corners again.
The diff is being covered by warranty but it will take 2 months for that to come through once I send the diff back Now I have to reinstall my old diff.
When I sent the diff back I found out that when the auburn comes apart, there is no connection between the input and output shafts. What I thought was clutch chattering in the the corners was actually the brake rotors rubbing and heating up in some irregular fashion.
Both brake rotors turned blue and warped pretty bad so I am scraping them. I figure that since the center of the locker and the spider gears fell out, the output shafts are allowed to move in and out which allows the brake rotors to rub the pads.
From what I observed, there is no need to remove the broken parts inside the diff as long as you remove the drive shaft. Once the drive shaft is removed the ring and pinion do not rotate and the parts will sit in the bottom of the diff.