last night i went to a KFC parking lot and there's a hill-like transition to the drive-thru.

my car is lowered about 1" and when i went over this hill-like transition my car got stuck when the front wheels went over the hill/bump. my left-rear wheel was off of the ground and the bottom of the car (driver side close to the front jack-point) was sitting on the asphalt.

what a disaster.

anyway, I figure the LSD would transfer torque to the rear wheel that is still on the ground, since there is no traction on the driver's wheel...but when I went in reverse, the driver's side wheel (the wheel off of the ground) kept spinning.

i figure my LSD does work because I've done the test of spinning one wheel and the other wheel does rotate in the opposite direction.

Does LSD just not work in reverse?

(FYI, by turning my wheels randomly I was somehow able to reverse out)

 

no , it does not. it would be pushing the clutches away from eachother.

 

No clutches on a torsen. The torsen requires a small degree of traction (mu above 0) to work. It is not a locked gear system that can work when one tire is in the air, which is why it is not specced for rear wheels on offroaders.

 

"center washers" which basically acts like a clutch ( and look like a clutch) mashing together, either way the side gears would be pulled away from eachother.

Hummers have torsen diff's all you need to do is press the brake down a tad and you have your one wheel in the air problem solved.

 

The side gears are either pushed together or pushed apart (against the Torsen housing), that is determined by which wheel turns faster = turning left or right.
The thrust washers are on both sides of the side gears.
That can be checked on the official Torsen website, look for the T-2 under "products".
http://www.torsen.com/index.htm
The thrust washers are not made of clutch like material IIRC.

With one wheel in the air, one wheel has zero (0) traction and the Torsen being a torque multipier you end up with zero (0) traction.
Anything x 0 = 0
The T-2R can transfer torque with one wheel in the air.

The Torsen works driving backwards.

 

I guess i stand corrected.....

But like i said before, apply a little breaks and your wheels will spin correctly.

 

then I am confused why my wheel in the air kept spinning and I went nowhere...

i would assume all the torque would transfer to the wheel on the ground and the wheel in the air would not spin...

 

i did this and the wheel in the air did spin.

this also burned my clutch quite a bit.

 

Its called brake modulation, both of the wheels should spin when you do this.

 

jyeung528 Posted on Dec 2 2008, 01:08 AM
The wheel in the air "used" all the torque, but it takes little torque to turn a wheel in the air.
Therefore there isn't much (almost none) locking power generated by the gears inside the Torsen housing to transfer torque to the other wheel.

Very simplified you could think about it this way: the harder you press your hands together while rubbing them together, the harder it becomes to rub them together.
The heat generated is the torque transfered.
More rubbing and/or more pressing = more heat = more torque transfered.
Now cover one hand with grease (=one wheel in the air) and even if you press very hard its still easy to rub your hands.
No heat generated = no torque transfered.