Detroit true trac

[Jack Bryant]

Hello my brothers , I am going to install detroit true trac to the rear of my 2002 kj 3.7. engine stock rear axles.
There is to much information for me to decide what I need.
Could anyone give me a hint on part numbers and benders, and what I need. Thanks Jack

 

[LibertyTC]

What size tires are you currently using? Planning anything larger?
This thread comes to mind. https://www.jeepkj.com/threads/rear-8-25-detroit-true-trac.57185/

 

[Jack Bryant]

What size tires are you currently using? Planning anything larger?
This thread comes to mind. https://www.jeepkj.com/threads/rear-8-25-detroit-true-trac.57185/

Running 255 70 r16 not going higher I'm happy with my 2.5 lift

 

[Jack Bryant]

What size tires are you currently using? Planning anything larger?
This thread comes to mind. https://www.jeepkj.com/threads/rear-8-25-detroit-true-trac.57185/

I Read the repost sounds like fun.. What if not DTT

 

[4wd728]

I had a Detroit Truetrac installed on the rear of my 2006 Liberty by a Jeep dealership. I just used the stock 3.55 rear axle ratio. Before the installation, I was in some muddy soil and one of the rear tires slipped. I was able to get out by putting it into 4x4 low. After the installation, for normal muddy driving, loose gravel, and wet road conditions, I just drive normally and I can hear the alternate gripping of each rear tire. Sometimes I just put my Jeep into 4x4 now just to hear that whine of the 6 speed manual transmission (in the appropriate conditions, of course). The design of the Truetrac is similar to the "Torsen" LSD on another vehicle I used to drive for 16 years with no problems. Both are all gear and maintenance free. The Truetrac is fine for the type of driving I do. It was a good investment, in my opinion. The part number for my Truetrac was Eaton (Detroit Truetrac) Part # 52688. A few additional parts were required to make it a wear free installation, but the dealership took care of that for a 2006 model. They, at first, suggested an "ELocker", but I wanted the all gear Truetrac and knew from experience that I would not have problems with it and it was automatic. The ELocker would have to be manually activated. I needed something that activated by itself quickly for the type of driving I wanted.

 

[tommudd]

4.10s and DTTs front and rear on the 03
Had ran them on two of my XJs as well years ago
04 had them for a while as well

 

[4wd728]

4.10s and DTTs front and rear on the 03
Had ran them on two of my XJs as well years ago
04 had them for a while as well

How did that front DTT handle in various conditions? I've been considering doing the front, too. Was the front end the OEM aluminum case?

 

[tommudd]

How did that front DTT handle in various conditions? I've been considering doing the front, too. Was the front end the OEM aluminum case?

Of course, the D30a as they all have
With a DTT they do so much better
The cause of so many getting busted up was people would start spinning, and when one tire would suddenly catch the gears tried to walk up over themselves and bust the case. With a locker in there, no spinning just walk up over everything
still running dual DTTs in the 03 which is about all I drive in the winter when snow, ice etc on

 

[4wd728]

Ok. thanks. I had read about the aftermarket front steel case from JBA (no longer being made, I think.). I have read that the steering with the front DTT installed was a little different. If not by much, then that would be just fine.

 

[tommudd]

When locked in it is a bit different but you get used to it quickly

 

[mercdudecbr600]

Ok. thanks. I had read about the aftermarket front steel case from JBA (no longer being made, I think.). I have read that the steering with the front DTT installed was a little different. If not by much, then that would be just fine.

In my experience, with the dtt in the front diff the steering is a bit different at all times. The steering is about 10-15% heavier and there’s a stronger steering return to center after turning. After a while of driving it’s not huge but at first it’s noticeable. For those reasons, oem manufacturers for advanced 4x4 models use a front lsd with less bias than the Dtt, or have disconnecting hubs. So I used synthetic oil in the dtt, which slightly reduces bias and helps steering.

 

[4wd728]

Thanks tommudd and mercdudecbr600 for that info. I have read another report about "return to center" with steering, but this was more detaiIed information. Thanks. Heavier steering is okay. I used to drive an old car with no power steering at all. I don't know what ratio I have in the front differential of my Liberty. If it is the same as the rear differential, then would it be okay to use a DTT with a 3.55 ratio the same as the rear? I have seen a front DTT advertised as 3.54, but someone that installed it said it was really 3.55. I'm just interested in street driving and light trail with this Liberty. I've done rock climbing, but that was in another designed for purpose vehicle. My other car has a Torsen 4.10 ratio in the rear and the engine RPM can go as high as 4000 during a normal highway drive in 5th gear (with a 5 gear shifter) at around 60-65 mph. I'd like to keep my differential RPMs the same as stock for now in the Liberty. I've driven in all weather conditions with Torsen including ice and snow packed mountain sides and never had problems with traction.

 

[tommudd]

I never notice it being heavier steering when not locked in

 

[mercdudecbr600]

It’s subtle, but at least for my rig, noticeable right after install. Now I barely even think about it/notice it.

It makes sense because even without the tc engaged, the front dtt is trying to balance the turning of both wheels. So now when turning you have twice the wheels to turn and to overcome the bias of the diff - that’s why the steering is heavier. I think if my dtt was any tighter, on u turns,
I would be scrubbing the front inner tire. It’s also possible that as more miles get on the diff it loosens up a bit. But like I said, I used synthetic to help aid turning and that’s worked well for me so far. I also noticed that it tended to track really straight on the highway.

The dtt doesn’t change the ring/pinion, or gear ratio. It only replaces the carrier assembly. So what you have before is what you have after in the gear ratio Dept. You should be fine. I don’t think you’ll be disappointed in the dtt, IMO it’s almost the perfect traction aid.

 

[tommudd]

Would never, ever run synthetic in diffs
I run 85-140 front and rear full on dino

 

[4wd728]

mercdudecbr600 and tommudd, thanks again for the information. There was a lot of detail here and that was much appreciated. I think the detail here is better than on other sites I've been on. I will like the DTT on the front end of my Jeep. mercdudecbr600 I saw that you had an e-Locker in back. Is it possible to use that locked at highway speeds at around 65 mph? I have another vehicle that I was considering a locker for the back. It might be off topic to talk about the other vehicle here (It is a 42,000 lb truck chassis). The locker I had considered for that was a Detroit NoSpin Automatic Locker. The description on the Eaton site said that it was not for everyday driving since it was designed to be used for aggressive traction. https://www.eaton.com/us/en-us/catalog/differentials/eaton-detroit-locker-differential.html
The existing OEM axle for that vehicle could have come with an air locker only and I cannot find a DTT anywhere for it and there is an air supply line nearby. Do you think an e-Locker would be more reliable (or simpler) than an air locker? Mainly, I'm just interested in getting out of a bad road condition at low speeds with that vehicle and I only drive it a few times a year. It would have been nice to have a DTT back there just for all around safety. I'm still looking around for some kind of unit to fit back there, though. The OEM manual said that the OEM air locker had splines on the axle where the locker collar was actuated by a fork. Alot of extra parts would have to go in. I'm thinking an e-Locker or air locker maybe at low speeds would do the trick on that vehicle. I read somewhere that fully locked at higher speeds on ice might not be a good thing. Sometimes one can just hit a patch of something even at low speeds and get some feedback. I drive slow in those conditions anyway even with the DTT. tommudd if you know something about the lockers, too, thanks for any advice.