What will cause a detroit locker to not work at all? Anytime I get one tire off the ground or little traction only one tire spins. Its been like this since I bought the Jeep about and I just pulled the diff cover off to change the gear oil and confirm it actually has a locker.

You sure its actually a detroit? Sounds like a Limited slip or a tru-trac action. When Detroits break, usually nothing spins or they both spin........your mileage will vary.

99% sure it is a detroit. The guy I bought it from said it had a detroit locker and when I pulled the diff cover off yesterday I looked up a detroit locker online for a chrysler 8.25 and they like identical. I wish I would have taken a pic.

Jeremy, when you had the differential cover off did you inspect the lock pin? Also check the bolts that holds the two half's together. Either a broken pin or lose bolts can cause the locker to not work right. It could also be a Detroit Trutrac and not a locker, there is a similarity between them and to many people call any traction enhancing differential a locker.

yea, the detroit locker has 8 or so bolts exposed on the non-ring side and the trutrac is more smooth of a case.


Detroit locker



Detroit Tru Trac


usually when a detroit locker breaks, it takes a shaft with it, and the detroit locker for that axle is rated to somewhere around 800hp. so if it broke, you would know it.

Going by the pic I have the tru trac. Does it work differently than most lockers?

Yes, because it is NOT a locker. It is a Limited Slip or posi dif. This means it is basically a tight open dif. More traction than OPEN as long as all the wheels have traction.

Ok that makes more sense now. Both wheels need to be on the ground for it to work. Now there are braking tricks and e-brake tricks you can use to make the tru-trac has both wheels on the ground and that will aid when you have one tire in teh air.

Yes, it is NOT a locker. It also is NOT a Limited Slip and posi is a GM term for their LSD so it isn't a posi.

A Detroit TruTrac is a gear driven, torque biasing, traction enhanced differential. There are no clutches as in a LSD so no worn clutches discs to replace. Next to a locker the TruTrac is the best differential for use on a wheeling rig.

Ok thanks for the input. I'll try the brake trick next time I have a tire off the ground.

According to Eaton's website, the mfg of the truetrac, it is in fact a LSD. It's a helical gear driven LSD. Not all LSDs use clutches.
The one I had was about as useful as an open diff. On a light rig with big tires they won't lock up worth anything and it's hard to use the brakes when it's in the front and you're climbing a hill or rocks.

Sorry, but there is no slip in the TruTrac, yes it is helical gear driven, but it is a torque biasing differential which is suppose to transfer up to 40% of the available torque. It operates something like a LSD, but it isn't a LSD.
I've also had TruTracs one in the front and one in the back. The one in the front was worthless, the one in the back was less worthless, but neither was a locker.

i have one up front, and maybe it is different for auto trans, but mine is a maual and that thing locks up all the time. i have had 1 tire off the ground and it still spun the one on the ground. so it is different for all but i like it and it was un noticed on the street

I dont know for sure but there may be some confusion here on what the slip in LSD actually is. Slip % is the difference in spin rate between one wheel and the other that the locker will allow. if its 40%, it will let one tire spin 40% faster than the other. There most definitely IS slip for an HLSD, its not clutches slipping like in a VLSD but thats not why its called a limited slip anyway

Yes, I was wrong. I checked some of my information and although it is actually a torque biasing differential it is also a limited slip.