The other day I was moving my car from one garage stall to another when I got stuck on a patch of snow/ice. One rear tire was on wet pavement the other was on the aforementioned slippery stuff. I installed a Zexel Torsion posi unit last year and it has worked great on dry pavement. However, I thought it was quite strange that I got stuck on the snow and the other tire on the pavement wouldn’t spin. What’s up with that? Is that normal behavior for the Zexel unit? Was it just not experiencing enough torque resistance to shift over to the posi mode? Any insight to this?

 

yes, that is normal on a Zexel Torsen since it is a torque style posi, needing some resitance on one wheel to power the other.
If one wheel has 0 traction then that wheel will just spin.

When you raise the car up, the wheels spin opposite making it look like an open differential.

 

Cool, that's what I thought. Do you know how exactly that posi works? Does that solid block (the one held in by the bolt/pin) have to physically shift over to engage the posi?

 

here, take a read of this,
http://www.torsen.com/general/general_faq.htm

 

Excellent! Thanks

 

I just put one in also, right now i cant hook up too good on cold dry pavement. it spins one alittle more than the otherside but u can tell its trying. i know it works though because it does burnouts fine and i can swing the *** end out alittle in turns, but its definitely a touchy kinda posi. hopefully with drag radials it will dead hook on both tires.

well worth 100 bucks, my stock posi was really shot.

 

it works great when launching in a straight line, but cornering hard and getting on it, it just spins the inside wheel,
check out this vid to see it happening,
http://www.transamws6.com/video/manny-acu4.wmv

 

never had a problem with mine doing that in my camaro, then agian, ive never autox'd it either.

 

http://cablespeed.com/~jim3rdgen/12302Mdformula350.WMV

it was alittle wet, u can hear it trying which is better than stock posi i blew up, i couldnt even swing around turns at all without the one tire going crazy

 

Ya, if you don't road race or auto-x, then it's fine. they make a torsen, model T2R that has pre-load built in to fix the problem with the inner wheel spin. A lot of racers put this diff in thier car. I'd have it as well but I got a helluva deal on the rear I have now, $350 with Eaton Posi, 4.10 gears and it only had about 1000 miles on it. I've got to give the moser axles back eventually when we put a set of 4.10's in my buddy's 02 WS6.