I have a 2003 Forester 5 speed (therefore no limited slip rear differential).

 

So, with a regular differential in the back, and a regular differential in the front, does this mean that if one wheel in the front loses traction and one wheel in the back loses traction, then I have no traction? The reason I say this is that a regular differential will split the TRQ evenly, so if the wheel on one side goes to 0, then 0 goes to the other wheel.

 

So for instance if both right wheels say are on ice (Assume near zero friction), then I'm not going anywhere. If I am wrong about this, please explain why.

I have a 2003 Forester 5 speed (therefore no limited slip rear differential).

 

That's Forester _X_, therefore no LSD

While there are some more technical aspects to your discussion...

 

Essentially, you are right. If you have open diffs front and back, then you will not go anywhere if "one" front and "one" rear wheel have no traction and start spinning. This exact situation happened to me in my driveway last winter.

 

Commuter

Luckily absolute zero friction is rare, and if you don't floor the throttle, you should be able to crawl out of most situations.

 

Limited slip diffs are expensive and make most sense on high power 2WD cars, expecially front wheel drive.

As far as i'm aware this vehicle should have a centre viscous coupling which while in good condition will distribute drive to the front and rear at the same time ( to a point )my liberty has this even with 150k miles on the box it still works , i have picked front wheels up when offoading and still continued forward motion although i have seen another that did not! you can stuff them from abuse btw this a manual dual range

regards camo

That's why open diff AWD cars like most Subarus should be called more properly «all axles drive car» .

That said I drive in all kinds of winter road conditions and I've never been stuck with no traction anywhere.

I've even been up a short hill so slippery that when i went back down, I slided down right to the bottom with all wheels locked.

Any SUV with open diffs and AWD will have the same problem. And any SUV with 4WD and open diffs is even more of a problem because power is locked 50/50 and so any help the fronts could give you is only 50% of engine torque whereas an AWD car will be able to shift power to each axle to give you more help.

Actually, I view that as a benefit: If things are really slippery you don't want 100% of the torque on one axle! That would seem to be the point of 4WD

The center diff on the 90 legacy 5spd awd i bought in summer for $100 worked fine, and it had 230,000 miles on it. I know it was the sellers winter car because it had rust holes every were, i could see out the side of the car from were the jack was. I beat on that center diff prety hard, 1 wheel in the air on a hill and it just pulled it self up and over, with the front whell spinning. I did this alot becaus it lead to a good hill climb i only made twice, but the geo tracker never made it. Almost got stuck because of open diffs, one rear wheel in the air, and a tree in front of me barley made it out, it took about half an hour of trying, thought I burned the center diff up but it was good after that. I was origanly worried about burning cneter diff up, but after those experiances with a car with so many miles on it, it seems pretty strong.

DAN! GET ON AIM!