Flipping Detroit Truetrac gears? Rear in the front!? Anybody done this on something as big and heavy as a E350/D60???

[crazycaseys53]

Hello,

Hope this is in the right place, and sorry for the long post. I’m new to the Adventure Van thing. Scored a sweetheart deal on a low miles ‘98 7.3 E350 EB van that already had a high roof, gennie, and climate control system. I used the money I saved to buy a 4WD kit from Chris @ Ujoint, and after a year of finishing up other projects, I’m finally ready to start putting everything together.

This is a total budget build (I’m pretty handy, which helps), but I want to be able to go ANYwhere with this van. I started collecting all the parts and pieces almost a year ago, and as I’ve gone along my ideas of what I want/need are evolving. Initially I was going to build the van with a Truetrac in the rear dif (which I already purchased) and just run the front open, but after reading tons of Internet forum posts I’ve decided that I want more traction than that setup would afford me.

At first I thought Truetrac front/rear might suffice, but the more I read I think I want a proper locker out back.

That brings me to my question. I’ve found quite a few forum posts on other sites suggesting that you can put a rear Truetrac in a front axle so long as you flip the worm and spur gears inside the carrier. I’ve also read that “rear” specific Truetracs have a more aggressive bias than “front” specific applications, which sounded like it would match up good with a locker rear axle in such a heavy application. The problem was that the only information I could find on flipping these Truetrac units was on Toyota and Rover forums. Does anybody have experience with anything like this on a big one ton van? Both axles on my build are 35 spline Dana 60’s and both front and rear use the same carrier series. Also, my rear Truetrac is already out of warranty since I bought it 12 months ago, so I really have nothing to lose.

The only other plan would be to sell the rear Truetrac and buy a front Truetrac, but I figure I’ll lose at least $100 doing it that way...

Thanks for reading all of that!

I look forward to sharing some of my build as I get going.

 

[Binky]

Well, I might be interested in the rear truetrac, I've been planning on getting one for Binky anyway.
I don't need anything as aggressive as a locker.

 

[Len.Barron]

I'd just sell what you have and buy what you need, you don't want to find out that it didn't work after you've completely reassembled your front end...that's a lot of work..

 

[crazycaseys53]

Well, I might be interested in the rear truetrac, I've been planning on getting one for Binky anyway.
I don't need anything as aggressive as a locker.

Man, I’ve gone back and forth so much on that very sentiment. I literally spent about three evenings reading every single post I could find on the Eaton Detroit Truetrac, and I’ve found quite a few more examples of people VERY happy with them than people experiencing any kind of issues. I ultimately bit the bullet and decided to order a front Truetrac; I’m going to put the van together with one on each end, and see how it works. I was telling myself that having a locker on one axle would ultimately make the van so much more capable off-road, and even toyed with the idea of a front locker only, unlocking one hub in the snow, etc, but I really like the idea of the Truetrac’s torque biasing. I mean, if they’re good enough for the HMMWV...

I'd just sell what you have and buy what you need, you don't want to find out that it didn't work after you've completely reassembled your front end...that's a lot of work..

You’re not wrong. I think it CAN be done, but I don’t want to do it to a brand new dif...

 

[djbonsu]

Not sure how much hardocre off-roading you be doing but I think you will be happy with the performance of the true-trac. I have one on the rear and I have not had any issues since installed. I may be looking to get one in the front as well.

 

[Bikersmurf]

How heavy is the front? Rear?

I’d consider True Trac in the rear and arb in the front... for better drivability.

I’d not go that route in my ambo though. With 6000+ on the rear wheels and only 3000 on the front, the rear would be my focus

 

[Binky]

So, I have a Quaife on my FWD Saab (Frank) and love it! It's the same basic design that the true-trac uses.
I would do the true-trac front and rear if I could afford it. Odds are, if I need the extra traction, it's for snow and mud and I don't want a locker for that.
In 15 years of driving F-350s for my job, I can count on one hand the number of times I have used the locker on my F-350, and I take it stupid places.

 

[Mundo4x4Casa]

I have True Tracs in both axles ( a front Dana Super 60, which is mostly 35 spline Dana 70 parts including Dana 70 on/off hubs, except the housing and the RG&P, and rear 35 spline Dana 80) and am very happy with the result. After putting a wide splay of of traction aids in 13-4WD's, these are the most transparent and user friendly. I don't think there is any difference between front and rear in application. Here are the T.T.'s for a front Dana 30 (my XJ), and a front Dana 80:






You reuse your original RG&P.
We are just back from 10 days in Canyonlands/Moab country trying our hand at The White Rim Trail and Elephant Hill in truck campers. The mud was endless goo and I slid right off the road to Beef basin a number of times because of the nature of the True Tracs: namely that if you have no differential in the amount of traction, they both acted like a spool, locked up side to side. Even on the slightest angle in the mud, I would slide to the downhill direction, just like a full locker on both ends. On solid ground and especially rocks, of which we had a snootful, we never spun a tire on our 10,400 pound gorilla. We fared much better in the snow, which up high was everywhere. I'll do a T.R. on the longer-than-a-week page. The title will be, "Canyonlands: The snow above and the mud below." Take a good look below. A new girl is coming to town. The 21 year old Lance Lite 165-s xtracab, which has been superb is being put out to pasture, replaced by a custom ordered Lance 865 with no oven, no air conditioning, no microwave to keep the weight down and add more storage. The two have exactly the same footprint. jefe.

 

[crazycaseys53]

I appreciate the multiple endorsements that you guys have posted. There are always a handful of nay-sayers when discussions about these differentials come up. I have heard (read) the gamut, from they won’t work on heavy vehicles (binding), they’re not made well anymore, they really don’t lock up very well, they lock up too much, and anytime one tire loses even a bit of traction you’re stuck. But then there are always just a ton of people who swear by them (and are actually using them in multiple vehicles). In a perfect world, I’d have E-lockers front and rear, but these Truetracs will have been closer to 1/3 the best price I’ve found on a pair of E-lockers (I got the rear on sale at Summit over the holidays for $450, and the front just cost me $565 from Jegs), and I’ll use the difference to put a winch on the front to get me through what the diffs won’t handle. I’ve got a total budget of $20,000 for this project (including vehicle purchase price), and selectable lockers would have just eaten up too much of it, for questionable reward, considering I really don’t know how crazy I’m going to get with this beast of a van...

How heavy is the front? Rear?

I’d consider True Trac in the rear and arb in the front... for better drivability.

I’d not go that route in my ambo though. With 6000+ on the rear wheels and only 3000 on the front, the rear would be my focus

I haven’t found a scale where I can get a good front/rear split. In 2WD form, with a more or less empty cargo area I’m at 7000 lbs on the nose. I figure I’m going to add 500 lbs to the front with the 4x4 conversion and probably 1000 lbs to the rear with the interior build out, for about 8500 lbs total. Are you sure your Ambo is only 9000 lbs? I’ve heard quite a few people say the Truetrac won’t work with heavier axle weights, but there seem to be quite a few folks who have heavier rigs (Sportsmobiles) and like their Truetracs...

 

[Bikersmurf]

Years back. when it was completely empty the road side truck scale put it at 2700 lbs front axle and 6000 rear. I’ve weighed it more recently with a wack of stuff and a couple passengers in it, and it was +10k. I’m not 100% sure of the accuracy of the scale at such a “low” weight... but they are supposed to be fairly accurate.

 

[Burlydirtyhippy]

9500lbs here. Truetrac in the front and factory limited slip in the rear, we are extremely happy with this setup. Have put it through the paces on multiple terrains, although the majority of 4x4 time is in deep sand.

 

[crazycaseys53]

Years back. when it was completely empty the road side truck scale put it at 2700 lbs front axle and 6000 rear. I’ve weighed it more recently with a wack of stuff and a couple passengers in it, and it was +10k. I’m not 100% sure of the accuracy of the scale at such a “low” weight... but they are supposed to be fairly accurate.

Is your rig diesel?

I’ve heard quite a few people say the Truetrac won’t work with a lot of axle weight; not sure where “the line” would be, as it’s made for a Dana 60 which has a 6500 lb GAWR rating in stock form. I can’t imagine Eaton would make a diff that, along with the required axle upgrade would lower the effective GAWR, but I AM pretty green when it comes to all this stuff...

I’ve considered attempting to sell my Onan 4K generator and giant rooftop AC box in favor of a 2k Honda gennie and a Maxx Fan...which is honestly all I need. I imagine that would save a few hundred pounds. I’m considering this, because unfortunately one of the ways I am going to keep this rig on such a tight budget is buy fabbing all my own expo equipment (bumpers, racks and carriers, etc), and I’m most likely going to make all this stuff in steel. I do also intend to tow on occasion with this rig.

I have a great deal of respect for Chris at Ujoint, and he did tell me not to use a Truetrac on the rear of my van (unfortunately this was after I had already bought the part), and said quite plainly that they have issues binding up, especially when towing. The only instance of this that I have been able to read about on the forums was on Ram 3500 with a 3 car goose neck and something like 13k lbs of cars loaded on it. I can’t imagine that guy wasn’t over his weight limit, but maybe not...

So this is why I came on here asking about flipping the gears to run the rear Truetrac I had already purchased in my front diff and buying a new Detroit Locker for the rear. The consensus seemed to be not to do it (Chris told me in an email that I couldn’t do it also), and so then I started reading every Truetrac thread I could find on this site, the Sportsmobile site, and all of the Diesel truck forums...the more I read, the more accounts I found of people running the rear Truetrac without issue; in heavy trucks towing, in heavy vans, etc. They seem to be sensitive to running a quality mineral based oil without friction modifier.

I don’t know...I already have it, and now I have the front too. At the end of the day I had read vastly more accounts of people complaining about the Detroit Locker than I did of people complaining about the Detroit Truetrac. And a selectable locker has just never been in the budget for this build. Maybe some day...but not if I want to get my van on the road this season.

On a side note, do people dig build threads on this site? Should I do one? I’ve never done one for any of the other cars or trucks I’ve built (all hotrod stuff), but I’ve always kinda wanted to...

 

[Smoker]

The only flaw I see in your analysis is the budget. In my experience, it's the first thing to break.

 

[crazycaseys53]

The only flaw I see in your analysis is the budget. In my experience, it's the first thing to break.

Hahaha! I know all about that, but I love a good challenge just the same. That’s where the amendments come in. ? I’ve already amended my initial goal of $20,000 total budget to $20,000 running and driving and off on our first camping trip. Either way, when I started looking the best deal I could find was about $25,000 with a half-completed second hand Quigley conversion (still stock 2WD trans, no transfer case, etc), a bunch of rust, and something like 225,000 miles on the clock.

I’m currently at about $15,000 all in, and I’ve acquired all the same bits and pieces (except mine are from Ujoint), and now I just have to put it all together...

I’m thinking I’ll probably go over, but with any luck I’ll still keep it under $25,000. And my van only has 88,000 miles on it! ?