[RockyMtnRay]

Originally Posted by molex

I agree. In fact, I didn't know that my truck had LSD until I read this very thread and went out to look at my window sticker (keep it with my papers in the truck). I've actually read a few things on this forum that made it sound like the LSD hurt snow/ice driving performance. If I am correct, what happens is: On an icy road, when one drive wheel loses traction and begins to spin (slip), the LSD (by design) doesn't send more tourque to the slipping wheel, and instead sends some to the non-slipping wheel in an attempt to counteract the traction-less wheel. Problem is that on ice or snow, that extra tourque can cause the non-slipping wheel to lose traction so that now you have two traction-less wheels.

A non-LSD system (I think) would send more tourque to the slipping wheel (thinking that it's making a turn, so needs more power), but none to the non-slipping wheel, meaning that the non-slipping wheel would maintain traction so you could drive out of the bad spot.

It makes sense if you think about it. An LSD would be great in 4wd situations where it's dry, because the extra torque to the wheel with traction would help. But in the snow and ice, I think it would be a detriment.

Any verification out there?

LSD **can** be a detriment when both rear wheels are on packed snow or solid ice because they both will tend to spin, hence little lateral control (rear of the truck will slideways). I emphasize the packed snow or solid ice part because in deeper unpacked snow (where the tires will be in ruts and will have some resistance to sideways movement), having torque on both rear wheels (even if both are somewhat spinning) will often be enough to get you going.

Similarly if the ice isn't solid...for instance is only under the curb side tires on the side of the street or road....then the LSD will transfer torque to the side that's setting on dry ground (or at least less slippery) ground. It's fairly common to have intermittant ice in each tire track on a highway or have one side only on ice (like trying to pull out of a parallel parking space)...in these situations limited slip really shines.

There are many different kinds of snow conditions (e.g. cold, dry, wet, packed, loose/fluffy, dense/drifted, crusted over loose, etc.) and even several different kinds of ice conditions (e.g. cold, wet, black, etc.). A little known fact is that ice (and packed snow) gets stickier (has higher friction) the colder it gets...for instance, an icy road at -40 degrees is actually not very slippery at all. So it's real hard to make blanket statements like LSD is always good, or LSD is always bad when you're dealing with icy or snow covered roads.

All things considered, as a person who lives in a semi-snowy region...and who regularly ventures into the very snowy Colorado mountains...I am very glad my truck has both 4WD and a LSD on the rear axle. When I bought my Tundra back in October, I would only look at those which had both...and, to my happiness, all the trucks at my region's dealers did indeed have both.

Clearer now?