TrueTrac Limited Slip in the front?

[SUMOTOY]

I've never heard of any situation where this has happend with a Truetrac (locking in mid-turn). It is not an auto locker it's a LSD and they never achieve full lock under any circumstances. They are very predicatable and I've never had a problem with one in any of the vehicles I've driven including my own.

An auto locker is a whole nother story and I would never say that it couldn't happen with one of these. That's why I would never suggest putting one in the front of a full time awd like the 80 series. You just never know for sure if it is gonna lock up in a situation that it shouldn't.

Kenny:
I find torsen gear type LSD to be very predictable in the front or rear axle, and my post was directed at front clutchpack or front autolocker. I don't agree that a torsen/true trac can't and won't lock up in a turn, that's what it's designed to do. My point is that it's progressive lockup up to actual wheel spin, so by the time any wheels are spinning in the front (and possible loss of control), the True loc has already fully allocated the torque transfer.

My point to the HF2AV is that a VC can cause more understeer with a front True Trac because it can allocate more than 50% of engine torque to the front axle = more understeer. I still agree that the linear application of torque transfert negates any ascription of "danger".

One more thing. There are several production vehicles that come with front LSD's from the factory. Including the Acura TL 6spd, Mitsubishi EVO MR 6spd, Subaru WRX STI, Honda Civic SI, and even the piece of crap Dodge Neon turbo (although it's fast) plus a few more. There has not been a single negative incedent related to the front LSD.

Excellent point. I used to race and DD a Dodge GLH turbo. I installed a quaife (torsen/true loc type gear) LSD in my daily driver without any issues. There are thousands of FWD VW's with quaife front LSD's in them as well. And Quaife makes dozens of FWD applications, more than the True Trac actually.

The old Audi 4000 Quattros used to come with selectable lockers, but they eliminated that in 86. I think it had something to do with rally racing and they needed to have it on production vehicles in order to keep it in thier race cars. Those cars had amazing traction and were so much fun to drive.

Audi history (that I know well
The 4000 quattro used air (vacuum) lockers center/rear through the end of the model run in 1987. Then replaced by the 80 series quattros, these ran torsen center, air locker rear. The center and rear air lockers were in the 5000 series sedans and wagons thru 1988, then again replaced with torsen center, locker rear thru 1994. The v8 flagship ran an electronic clutchplate locker center and torsen rear in the autoboxes, and torsen center/torsen rear. As of 1995, Audi ran torsen center and ABS traction control (EDL) on the front and rear diffs. That is still in use today. Audi NEVER ran a LSD or locked *front* diff in any production quattro. In WRC rally, Audi ran locked all the time in the center. The rear was either locked or clutchplate LSD, locked more common. The front was either locked (always along with center and rear) or open, with only a couple rally's where they used (driver preference) a 20% locking VC. The easiest to drive IMO, was the locked front/center/rear, but it got interesting in tight turns on tarmac.

ST
94 FZJ80 SC
1991 V8 Quattro - Clutchplate center locker - torsen rear
1984 Audi Turbo quattro coupe - air locker center and rear

 

[Toyminater]

I think we have a new Crawford!

There is always one of these guys on every list. What would a list be without an armchair expert.

Armchair Expert? have you read any of sumotoys posts? he is more than an "armchair expert" he has first hand knowledge of many cars and their operating systems, and has offered quite a bit of knowledge to the MUD forums.


FWIW, the tru trac is an awsome front diff. you CAN lock it up by applying brake pressure when you have a tire lifted off the ground and it WILL transfer torque to the tire with traction. its the next best thing to a locker period.




T

 

[ShottsUZJ100]

its the next best thing to a locker period.

In an 80 maybe. In a 100 or FJ Cruiser/Runner/GX....TRAC is the next best thing.

 

[GXO]

We could always hack the ATRAC ECU into a later model 80 with ABS hehe

 

[ShottsUZJ100]

We could always hack the ATRAC ECU into a later model 80 with ABS hehe

Ya, I was just being a wise guy above. (Obvious, huh? )

 

[RedTacoma]

I am going to piggy back on that thread.

I was wondering if anybody has his Daily driving truck with Truetrac up front and LSD or locker on the back?
If they do how your is adjusting to it?
Anybody in some snow/ice capitol?

 

[WarDamnEagle]

I am going to piggy back on that thread.

I was wondering if anybody has his Daily driving truck with Truetrac up front and LSD or locker on the back?
If they do how your is adjusting to it?
Anybody in some snow/ice capitol?

You don't want a non-selectable locker in the front of an AWD. If you have front locking hubs then go for it, otherwise, don't.

 

[bpassmore]

You don't want a non-selectable locker in the front of an AWD. If you have front locking hubs then go for it, otherwise, don't.

truetrac are actually gear based LSDs. they do very very well in the front of a rig. it is not a locker per-se.

 

[RedTacoma]

You don't want a non-selectable locker in the front of an AWD. If you have front locking hubs then go for it, otherwise, don't.

Agree to the extent. Except
a. Truetrac is not a locker
b. We talking about driving on Ice/snow with kids on the back


Auto Lockers are out as they are not smooth enough.

Need to be a gentle aid to traction ...

My only worry is a steering influence and women view of that. Hence looking at others dealing with that.

 

[Nay]

I would rather have in a rear auto locker / front True Trac setup than selectable lockers in an AWD application.

I had this combo in a previous rig, and it was so predictable and effective in winter conditions - outside of really knowing how and when to use selectables, I don't think you can build a better "point and shoot" winter 4x4 setup.

My thought is you don't want losing traction and then trying to compensate or get out of trouble by switching on lockers. You don't want her to lose traction in the first place, even if the dual locked setup is ultimately a higher level of capability.

You take the dual lockers to get out of the ditch, but the rear auto/front TruTrac to stay out of it in the first place.

 

[retrofive]

I like this thread. Fun to hear all the opinions. Im currently un-locked. Everything from the forums based on how I drive, want, and ability leads me to these: My ability off-roading as driver has far to go even to match my un-locked 80 capabilities. Aussies sound like a good traction device added to the rear when I feel I could really use them, again based on driver ability. ONCE there (as driver), I wouldn't be going with a LSD in front, I prolly would be in the market for full lockers.

So long (un-educated) story short. I wouldnt run LSD in the front of my 80, and save whatever pennies for what I really need down the line. Who know's I may never really need front lockers. Sorry hope thats not blasphemy, but more of the just reality of where I am with my 80.

Just MO and .02.

 

[4LLC]

I put limited slips front and rear in my t100 and regreted putting them in .They never "locked up" when i need them most and on a snowy road they were down right scary when in 4wd .