Truetrac Differentials

[W650Mike]

I didn’t want to highjack garberz thread on Detroit Locker vs. Soft Locker but it brought to my attention to ask about the Eaton / Detroit Truetrac Differentials installed in my ’73. My PO provided me with a number of receipts, one of which shows axle / diff rebuilds by 4 Wheel Parts / Austin wherein they added Truetracs (and new gears, seals, bearings, etc.) fore and aft.

I’ve read up on these on Eaton’s site and understand the basic functionality – and, most importantly, I’m not having any problems with either axle, but I don’t see much if any posts here or on other sites about the Truetrac.

My questions are: Are these decent differentials for what is mostly street use and limited light duty off-road? Is there anything I should be aware of or watch for (such as maintenance peculiarities)?

Thanks

 

[NYLES]

Keep em oiled N enjoy! Have one in my front.

 

[bmc69]

I didn’t want to highjack garberz thread on Detroit Locker vs. Soft Locker but it brought to my attention to ask about the Eaton / Detroit Truetrac Differentials installed in my ’73. My PO provided me with a number of receipts, one of which shows axle / diff rebuilds by 4 Wheel Parts / Austin wherein they added Truetracs (and new gears, seals, bearings, etc.) fore and aft.

I’ve read up on these on Eaton’s site and understand the basic functionality – and, most importantly, I’m not having any problems with either axle, but I don’t see much if any posts here or on other sites about the Truetrac.

My questions are: Are these decent differentials for what is mostly street use and limited light duty off-road? Is there anything I should be aware of or watch for (such as maintenance peculiarities)?

Thanks

Having built axles for many a long year..I happend to rate the Truetrac as the best overall limited slip axle ever invented. The slightly less effective but incredbly reliable Auburn LS is my second choice. My .02

 

[jw0747]

I happen to rate the Truetrac as the best overall limited slip axle ever invented.

x2. Had one in my front for years then went to a selectable. Virtually maintenance free if you check fluid level regularly. Has no clutches to wear out. Will be excellent for driving you described.

 

[Hank_]

I am hoping next month to get new front and rear trutrac's along with 4:56.1 ring and pinions. I have used the aussie lockers and the limited slip truetrac will be great for the kind of off road I do.

Henry

 

[Greg_B]

I have the tru trac in the front and it has worked flawlessly...

I was really pleased with it last winter when we got a little snow here in Georgia... I was able to drive it in 4x4 on the road just like it was an open differential and when I had to go through a ditch and up a bank through the woods to go around stuck cars it grabbed and stuck very well. Some one said it would not work if one wheel was off the ground but mine seemed to pull just fine in that situation.

Greg

 

[Quick & Dirty]

Some one said it would not work if one wheel was off the ground but mine seemed to pull just fine in that situation.

Greg

If both axles have one tire each with near zero traction, it will be an issue.

Dragging the brakes will put some load on the spinning wheels and divert torque to the tires with traction. The Truetrac and Torsen respond very well to this technique and is somewhat effective on even open differentials.

 

[bmc69]

If both axles have one tire each with near zero traction, it will be an issue.

Dragging the brakes will put some load on the spinning wheels and divert torque to the tires with traction. The Truetrac and Torsen respond very well to this technique .

Exactly..and that technique is uniquely effective with the TrueTrac by virtue of its design. The maximum torque bias from any limited slip is achieved the TrueTrac but does require at least a 'slight' bit of traction on the tire with the least traction to produce the bias effect. If that tire is in the air..a little brake pedal suffices to produce that 'traction'..

 

[garberz]

If both axles have one tire each with near zero traction, it will be an issue.

Dragging the brakes will put some load on the spinning wheels and divert torque to the tires with traction. The Truetrac and Torsen respond very well to this technique and is somewhat effective on even open differentials.

That's what I have to do, with my open carriers. It works surprisingly well.

W650Mike, thanks for starting a new thread, this is all good info, and up to date.
Mark

 

[Steve83]

The TrueTrac is actually a "torque-biasing" diff; not really a limited slip. Others include the Zexel Torsen, & the old Gov-Loc used by GM. They function as totally open when the tires have equal traction, but progressively increase the bias to the wheel with less traction. A limited slip (like the Trac-Lok or Auburn) is always fighting its own clutches, even when you don't need any help.

This post contains links to most of the differential manufacturer's sites:
http://www.fordf150.net/forums/viewtopic.php?p=507588#507588

 

[NC-Fordguy]

Running a true track on the 44. It works pretty good but it ain't no locker. As stated in the above posts power braking helps when you have a tire off the ground. The true track best feature IMO is the ability to steer when the hubs are locked

 

[KyleQ]

I've got one in my daily driver FWD - LOVE it! Gear driven, so they will never wear out - I'm putting one in the rear axle of my tow rig for some extra traction. The only thing more aggressive out there is a Power-Lok.

 

[W650Mike]

Thanks guys,

Good info and one more thing I can move to the “Don’t worry about it” list.

 

[surfer-b]

Nothing but good things to say about the Tru-Trac, cant be beat for on/off road limited slip diff. I'v never had any issues with it.

 

[bmc69]

The TrueTrac is actually a "torque-biasing" diff; not really a limited slip. Others include the Zexel Torsen, & the old Gov-Loc used by GM. They function as totally open when the tires have equal traction, but progressively increase the bias to the wheel with less traction. A limited slip (like the Trac-Lok or Auburn) is always fighting its own clutches, even when you don't need any help.

This post contains links to most of the differential manufacturer's sites:
http://www.fordf150.net/forums/viewtopic.php?p=507588#507588

A very good point and certainly very correct..but like most who build difs I tend to lump them in two categories: Locking..and non-locking, the latter always getting called LS or limited-slip.

Interestingly, the amount of torque that a clutch-type LS can transfer across itself is still called 'torque bias' too. The maximum torque bias that the TrueTrac can achieve is about twice what a typical 'not worn too much' clutch LS can transfer.

I've had Auburns (which are a bullet-proof friction LS but without wear clutches) set up so tight (you can buy a range of springs) that they would almost match the performance of a locker on the trails...but my gawd the noise they then make on the road, particularly when backing up with a hot dif right after a lot of road miles. Sounds like the driveline is falling out..bit embarassing at the filling station when everybody starts staring at yr truck with wide eyes..LMAO.;D Nope..gotta love a TrueTrac.

 

[Steve83]

...I tend to lump them in two categories...

You know me: Mr. Specific! ;D I break them out into at least 8:
Spool/Lincoln-locker
Mini-spool
Open
L/S
Torque-Biasing
("True") Locker
Mini-locker
Selectable Locker (air, cable, electric...)

 

[W650Mike]

...So I dig out the receipts and documentation from my PO; get on 4 Wheel Parts’ site to search some of the part numbers (that have little or no description) and find – rather than Truetrac front and rear (as claimed in the PO’s list), I actually have a Truetrac in the D44 and a Auburn Pro Series 542043 LS in the 9”

http://www.4wheelparts.com/Drivetra...12&t_s=237&t_pt=5589&t_pl=9661&t_pn=AUB542043

I’m somewhat embarrassed that I missed this earlier, but it’s not the only surprise this truck has offered – some have been good; others, less so. All in all, it’s still coming together fairly well.

Thanks again for the input – sounds like I’m still “good to go” in the LS and Torque Biasing department. The Auburn calls for friction modifier which I didn't add when I changed grease about 3k miles ago. Hopefully no damage has been done.

 

[bmc69]

...Thanks again for the input – sounds like I’m still “good to go” in the LS and Torque Biasing department. The Auburn calls for friction modifier which I didn't add when I changed grease about 3k miles ago. Hopefully no damage has been done.

No damage would have been done but you do need that modifier to mitigate the racket it will make otherwise.

 

[Green76]

I've got 2 true-tracs installed in my 95 F150 running 35's and 4.56's with 65K miles on them, love'em. I pulled a stump out while on pavement and in 4wd Low and it left four equal skid marks 6 inches long at all 4 corners. I just recently installed a true-trac in my 76 Bronco rear. Probably install one in the D44 the first time I have to tear into the front.