Detroit Truetrac

[Jim McClain]

I am under the impression that a minimalist drivetrain, yet still trail capable, would include a Detroit Truetrac in the front differential. Correct?

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Although not as good as other types of lockers, this should work very well for the kind of trail driving I do and especially good for use in the kind of winters we have in Feather River Country, both on highways and trails in the snow. When using 2WD, I won't even know it's there, but in 4WD, it will make driving much better and safer for me.

So, can this be installed without removing the front axle assembly from the Jeep? I know switching to 4.10 gears will require the complete removal of the front drivetrain. I do plan to upgrade to 4.10s, but it's not in my budget right now, since I would have to do both front and rear at the same time. My hope is that I can make this DTT improvement now and do the 4.10 switch in a year or so.

Any guidance you'd like to offer? Thanks,

Jim

 

[tommudd]

Yes you have to pull the front diff to do anything except swap fluids in the front diff.
As far as that in the front its great, you do have to " lock it in " in a way but does great
An ARB locker is best this would just be a step down but still great

I think I would wait and do it all at once instead of paying twice for R&R

 

[HoosierJeeper]

x2.

If you're looking for some easier traction help, the rear is easier to mess with and would be less expensive to pay for twice. But my only concern with putting something in the rear is now you'll likely be doing tougher terrain and without anything up front, you're probably running a higher risk of shattering the front diff. I don't have any stats to back that up lol, but I feel like staying open/open is safer until I'm ready to upgrade front/rear. With open/open I'll be more likely to turn around. I'm not convinced either that just having something up front and the rear open will add that much capability either. From the KJs I've seen wheel, if they have one locker on, it's probably severe enough to have both axles locked. Granted, I've made it over the same terrain but with more hassle and tow strappin'. Driving with a front locker or LSD also requires a different method of driving, acts differently in slippery stuff.

Sorry for the wall of text. I'd vote for waiting till you can throw ARBs and 4:10s front/rear.

 

[tjkj2002]

I can vouch for the DTT,ran a front DTT and rear ARB for years in my KJ when it was still IFS and it was a very good combo on and off road.

 

[tommudd]

^^^ good advice for sure
With the DTT, you have to tap the brake pedal and kid of feel to get it to lock in. Guess what I'm trying to say with say a ARB, you push a button and lock it in, you know you're good to go. But with a DTT tapping the pedal to get it to lock in takes a bit of know how and finesse . Don't get me wrong, I love DTTs way better than any lunch box / cheap so called lockers.
Its just different than lock and go like ARB
For me I'd do DTT up front and ARB rear along with 4.10s at the same time.

 

[tjkj2002]

^^^ good advice for sure
With the DTT, you have to tap the brake pedal and kid of feel to get it to lock in. Guess what I'm trying to say with say a ARB, you push a button and lock it in, you know you're good to go. But with a DTT tapping the pedal to get it to lock in takes a bit of know how and finesse . Don't get me wrong, I love DTTs way better than any lunch box / cheap so called lockers.
Its just different than lock and go like ARB
For me I'd do DTT up front and ARB rear along with 4.10s at the same time.

Yeah I learned very quickly and it really saved on breaking parts since here in Colorado the trails can get really nasty with boulders and off camber that likes to break parts.

Made me slow down,make sure I have a good line,and use the unlimited crawl ratio of the auto to make alot of those trails much easier.Plus made the trail ride much more fun at slower speeds since I have a bad back.

 

[Cardhu]

having a lsd that works is great. DTT at top of list. no clutches, no additive, nothing to wear out. As noted, best choice for our front diffs to preserve its fragile-ish nature.

Since you have to replace the carrier, you'll be removing the existing ring gear off the stock carrier to remount, then setup for that carrier. All of which requires full removal of the front diff.

To remove the front diff you either need to cut the bolt on the cover guard skid plate or remove it from the cover guard.

If 4.10's are in the future, i'd save yourself the labour and do it at once. If you find a donor axle housing you can get them set up before hand.

 

[Jim McClain]

Yes you have to pull the front diff to do anything except swap fluids in the front diff.

I was afraid of that. Wellll, bummer.

I think I would wait and do it all at once instead of paying twice for R&R

I'd vote for waiting till you can throw ARBs and 4:10s front/rear.

If 4.10's are in the future, i'd save yourself the labour and do it at once. If you find a donor axle housing you can get them set up before hand.

Yeah, figured as much. I don't mind spending a lot of money on my KJ, I just don't want to pay twice for something.

I can vouch for the DTT,ran a front DTT and rear ARB for years in my KJ when it was still IFS and it was a very good combo on and off road.

I hadn't really considered putting a locker in the rear, but you guys make a good case. Although I'm not sure I will find myself in those kinds of situations. I do understand the concept of pushing the limits more, as the hardware improvements make it possible. But there's still no "group" of organized 4-wheelers here and the disorganized ones appear to be pretty cliquish, so I'd still be a lone wheeler most all the time. I'm acutely aware of my limitations and, as my lungs deteriorate, I'm less likely to rise up to the challenge of those more difficult trails by myself.

As much as I have grown to love taking my KJ to places I could have never gone with my minivan, I'm still primarily a landscape photographer who can't hike because of my health. I kinda like being able to show people what they can find in Feather River Country, even if they are disabled. But, I still need to be able to get myself OUT of trouble, if I happen to find myself in some while out looking for a nice photo.

I'll continue my search nearby for a front donor housing. This seems to be the best way to keep me from being without 4 wheels under me for too long. There's not many salvage yards close by though and none have had front diffs since I have been looking. I know that's going to be the most economical solution, but do any of you have opinions on this:

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Jeepin' By Al Custom made Dana 30 housing for replacing the aluminum Dana 30A

Just the housing is nearly 15-hundred bucks, but that would eliminate any worries about breaking the aluminum housing and make any future work far less expensive to do. It adds ground clearance and other benefits over stock housings. Beyond cost, what do you think?

 

[HoosierJeeper]

Won't add any clearance really, but definitely a good upgrade. Cost wise, it's probably not that far off from your original plan of pulling it out twice.

Another avenue...if you're not hell bent on lockers but want some "safety margin" and considering that you wheel alone, I'd look into a winch. Lockers will get you further to get stuck in an even worse spot. For wheeling alone, I'd go winch first over locker, at least then you can recover yourself, which is an ability lockers won't even give you.

 

[renegade 04]

I just had a DTT put in the rear and a Eaton electronic locker up front. I don't have many miles on the set up yet, but I hope to soon test it out and report back.

 

[tommudd]

JIM, IF YOU WEREN'T SO FAR AWAY ( whoops sorry caps )
I'd sell ya a good front diff cheap, think I have at least 2 maybe 3 with 3.73s in them, all good
But by the time shipping etc wouldn't be worth it

There has to be some yards out there with some, keep bugging them

 

[tjkj2002]

JIM, IF YOU WEREN'T SO FAR AWAY ( whoops sorry caps )
I'd sell ya a good front diff cheap, think I have at least 2 maybe 3 with 3.73s in them, all good
But by the time shipping etc wouldn't be worth it

There has to be some yards out there with some, keep bugging them

I shipped my old D30A and only cost me like $40 through fedex,they even had a box just big enough for it,packed it tight with those foam peanuts.It arrived to the buyer without damage.

 

[tjkj2002]

I hadn't really considered putting a locker in the rear, but you guys make a good case. Although I'm not sure I will find myself in those kinds of situations. I do understand the concept of pushing the limits more, as the hardware improvements make it possible. But there's still no "group" of organized 4-wheelers here and the disorganized ones appear to be pretty cliquish, so I'd still be a lone wheeler most all the time. I'm acutely aware of my limitations and, as my lungs deteriorate, I'm less likely to rise up to the challenge of those more difficult trails by myself.

If your not doing anything ******** a DTT up front will benefit you alot for those milder,and muddier trails to take your pics.Even in the winter when the roads are icy and snow covered just popping it into 4hi the DTT will amaze you around town.

In mud/snow/ice having better traction in the front is a little more important then the rear.

When I needed 4wd on icy roads here I never locked my rear ARB,big no-no in icy conditions.

 

[Jim McClain]

I shipped my old D30A and only cost me like $40 through fedex,they even had a box just big enough for it,packed it tight with those foam peanuts.It arrived to the buyer without damage.

That's damn reasonable. Hey Tom, if shipping could be under a hundred, what would you want for one of those diffs? Can we work this out? I don't know how much they weigh, but you could figure out shipping costs to the zip code 95971 and see if you'd be willing to do that. I'm sure it's somewhat of a hassle, so I don't know if it's worth the trouble for you.

 

[tommudd]

That's damn reasonable. Hey Tom, if shipping could be under a hundred, what would you want for one of those diffs? Can we work this out? I don't know how much they weigh, but you could figure out shipping costs to the zip code 95971 and see if you'd be willing to do that. I'm sure it's somewhat of a hassle, so I don't know if it's worth the trouble for you.

Going down home to my stash this weekend I think
I'll check for ya

 

[sota]

I was always under the impression that a DTT in the back and either the same up front or a full locker up front was the better arrangement for a mostly street jeep with occasional off-roading.

 

[Cardhu]

I hadn't really considered putting a locker in the rear, ....

well, you will have to set up gears, so its just the cost of the carrier adding to the problem( ie dollars).

You must be registered for see images attach

Jeepin' By Al Custom made Dana 30 housing for replacing the aluminum Dana 30A

Just the housing is nearly 15-hundred bucks, but that would eliminate any worries about breaking the aluminum housing and make any future work far less expensive to do. It adds ground clearance and other benefits over stock housings. Beyond cost, what do you think?

I love that thing but unless your doing 4.56, 4.88's They can keep it for 1500 bucks. Built with setup, 4.56 and a DTT gets pricey~3K ish for what it is/isn't.

I was always under the impression that a DTT in the back and either the same up front or a full locker up front was the better arrangement for a mostly street jeep with occasional off-roading.

I've never had trouble with a LSD on ice that getting off the gas didn't solve. Locked would definitely cause grief any time you turn.

 

[turblediesel]

I'm curious about the need to tap the brakes to engage a DTT. What happens mechanically when you do that?

Looks like a worm drive in the picture. Pinion gears can turn worm gears but worms can't turn pinions.

 

[sota]

I'm curious about the need to tap the brakes to engage a DTT. What happens mechanically when you do that?

Looks like a worm drive in the picture. Pinion gears can turn worm gears but worms can't turn pinions.

being a gear driven instead of friction driven limited slip, the diff needs a reference axle to be able to control torque splitting. if one side goes to 100% slip then the diff will act like a fully open one. tapping the brakes will create the needed reference torque on that side to cause power transfer to the wheel that has traction. note that tapping or riding the brake slightly is ONLY needed when you have a 100% loss of traction on one side. otherwise the diff will have the needed reference to do torque splitting.
it's also why I'm still of the opinion that unless you're doing a lot of serious off-roading, a DTT in the back is a great choice as it'll work on the streets in ways that will be helpful.

that's my basic understanding of it. note I have the FWD equivalent in my one car (Quaiffe) and it works under the same principal.

 

[tjkj2002]

I'm curious about the need to tap the brakes to engage a DTT. What happens mechanically when you do that?

Looks like a worm drive in the picture. Pinion gears can turn worm gears but worms can't turn pinions.

being a gear driven instead of friction driven limited slip, the diff needs a reference axle to be able to control torque splitting. if one side goes to 100% slip then the diff will act like a fully open one. tapping the brakes will create the needed reference torque on that side to cause power transfer to the wheel that has traction. note that tapping or riding the brake slightly is ONLY needed when you have a 100% loss of traction on one side. otherwise the diff will have the needed reference to do torque splitting.
it's also why I'm still of the opinion that unless you're doing a lot of serious off-roading, a DTT in the back is a great choice as it'll work on the streets in ways that will be helpful.

that's my basic understanding of it. note I have the FWD equivalent in my one car (Quaiffe) and it works under the same principal.

It works just like a Torsen diff and they all work better if the front.