Truetrac Failure

[eighty6gt]

Here I thought detroit lockers were bulletproof. I guess there's nothing.

 

[ZmanM3]

The OP had a Detroit trutrac fail not a locker, different types of diffs.

 

[Pentalab]

Here I thought detroit lockers were bulletproof. I guess there's nothing.

Nascar rules say they have to use detroit lockers.... which seems strange, if you are flying around corners..at speed, with your foot into it.

The OP had a tru-trac

 

[Norm Peterson]

NASCAR has plenty of picky (screwy?) rules, but there actually is some logic behind this one aside from keeping some very creative people from finding a more effective way.

But the "corners" that their cars have to turn through at speed are so gradual that the tires can accommodate the difference through combinations of longitudinal slip and slip angles. Understand that tire behavior out near the cornering limit is neither "stuck down" nor does if follow the rules of classic linear-range geometry.


Norm

 

[Pentalab]

NASCAR has plenty of picky (screwy?) rules, but there actually is some logic behind this one aside from keeping some very creative people from finding a more effective way.

But the "corners" that their cars have to turn through at speed are so gradual that the tires can accommodate the difference through combinations of longitudinal slip and slip angles. Understand that tire behavior out near the cornering limit is neither "stuck down" nor does if follow the rules of classic linear-range geometry.


Norm

I figured as much. Dunno what they are allowed to use on a road course, since they used to run 1-2 road courses per year..and actually turn right for a change.

Nascar has other rules too, like no more than -1 deg negative camber on the right front tire. Left front is zero deg camber. That's strictly enforced.

 

[Saleen304]

Same thing happened to me today. Had to open the diff to replace a weeping axle seal and noticed the metal pieces and broken housing. Bolts were loose and could be turned by hand. I took it apart and no internal damage so I plan to just tighten it back up and add some loctite.

 

[eighty6gt]

Maybe I should loctite the bolts on mine before I install the diff.

 

[Timmbo]

This is ridiculous. What are better options out there for a street/strip car? I might get the car to the drag strip one of these days and need something to hold up. Definitely don't want a spool since I wanna keep it streetable.

 

[07 Boss]

I've been telling people this for years and for some reason nobody wants to listen. The Tru-trac is a stout piece and it is great at what it was designed to do, BUT helical gear differentials are not meant for drag racing You can build them stronger but they are inherently a poor design for street/strip action.

If you're not wanting to run a spool or locker, the best option is a good regular old LSD, whether it be a Auburn Pro, or Yukon Duragrip, or Eaton Posi. The only other really cool kind of option in my book is the Auburn ECTED unit. It is an electronic locker that when it is not engaged acts as a normal LSD with power going to both wheels, not like an open diff. I have heard of some reliability issues in the past but I believe at the time they were looking at revising it.

 

[Saleen304]

This is ridiculous. What are better options out there for a street/strip car? I might get the car to the drag strip one of these days and need something to hold up. Definitely don't want a spool since I wanna keep it streetable.

To be fair, this unit has been in the car since 2006 and has been down the drag strip >100 times. I am still gonna use it. Just needed to loctite the bolts and let her rip. There was no damage to the helical gears inside the diff.

 

[Pentalab]

Maybe I should loctite the bolts on mine before I install the diff.

Yeah loctite everything. And if you manage to still break it....another possible option is the 4 x pinion version tru-trac ( with the stronger housing)..... but the beefier version requires 33 spline axles. Still, either version...with loctite, at least won't have bolts backing off on you.

If you really wanted to go crazy, I suppose you could even use red loctite.

 

[eighty6gt]

Damn right I'll use red, blue is kids stuff.

Both probably dissolve in gear oil.

 

[RED09GT]

I second ZmanM3's opinion on the locker. I've got Yukon's Grizzly Locker, which is supposed to be an improvement in streetability over the Detroit locker but it is still pretty annoying and quirky. It feels exactly like my Detroit locker in my fox body car.
It definitely degrades the daily driving experience and people stare as you "hop" into parking spaces. You also have to adjust your driving style around some curves as too much throttle can cause the car to push pretty heavily.

It is great at the strip though and leaves impressively perfect evidence behind on the street while having some fun.

 

[05stroker]

I guess I will consider this the part where I have been lucky.! My car has had a Truetrac since I started building it. I have been though 6 motors beating the shit out of my car, pushing it to its limits of the parts I have on it. I don't even know how many times I have launched the the car at the track, its a lot. The Truetracc has worked for me. I however have not launched on the trans brake yet though! I leave at 2500 on the foot brake and pull 1.35 60 ft and 1/8 at 5.78@123mph. I do consider it the next weak link. I am not going to a spool though, I like to drive my car on the street as much as the track. I may look into one of those electronic lockers when the time comes. I have no issue upgrading to 33 spilne at that time if needed as well.

 

[swflastang05]

Chromoly Spool FTW! I dont mind my spool on the street, it takes some getting used to but it's not bad after you get used to it. The only thing that sucks is if you ever have to push the car, then it's pretty much impossible to turn, car comes to a stop soon as you think about turning that wheel.

 

[Norm Peterson]

Don't think I'd want to drive a car with a spool in the rain. Forget about in the snow/slush that some of us see at least a few times a year.


Norm

 

[Pentalab]

I guess I will consider this the part where I have been lucky.! My car has had a Truetrac since I started building it. I have been though 6 motors beating the shit out of my car, pushing it to its limits of the parts I have on it. I don't even know how many times I have launched the the car at the track, its a lot. The Truetracc has worked for me. I however have not launched on the trans brake yet though! I leave at 2500 on the foot brake and pull 1.35 60 ft and 1/8 at 5.78@123mph. I do consider it the next weak link. I am not going to a spool though, I like to drive my car on the street as much as the track. I may look into one of those electronic lockers when the time comes. I have no issue upgrading to 33 spline at that time if needed as well.

http://www.vmpperformance.com/product-p/dts-913a561.htm

http://www.vmpperformance.com/product-p/dts-913a701.htm

If u used loctite on the heavy duty 33 spline / 4 x pinion per side LSD, I think you would have a hard time breaking it. The various lockers mentioned are superb for strip use.... but if it's a DD, that also has to go around corners..... including wet wx, either version of the tru-trac might be just a little safer.

 

[ZmanM3]

I purchased a Boss torsin diff, and I have 3:73 gears. Its a step down from the 4:10 gears but with kids and limited time the car is pretty much a pure street car at this point so I'm going to make it more that way. I also go Steeda caster chamber plates and new bushings for the rear suspension parts. Once its all on I think it should be a much friendly ride for driver and passengers.

 

[fdjizm]

Count me as a lucky trutrac owner here as well.

 

[Sky Render]

I purchased a Boss torsin diff, and I have 3:73 gears. Its a step down from the 4:10 gears but with kids and limited time the car is pretty much a pure street car at this point so I'm going to make it more that way. I also go Steeda caster chamber plates and new bushings for the rear suspension parts. Once its all on I think it should be a much friendly ride for driver and passengers.

Do you plan to drag race? Because that Torsen is going to explode if you launch it too hard.