Dave C., Yes, at least one of the axles has to turn when the driveshaft is turning. The clutch pack under spring pressure tries to make the axles act as if they are locked together like with no differential, but enough resistance to turning on one wheel forces the clutches to slip and the power goes to the other wheel and also allows it to turn faster. (Like when turning so that the outside wheel can move faster than the inside one and you can turn. That is what they mean by "limited slip". The clutches limit the amount the wheels can "slip" against each other. If the clutches are held by too much spring pressure, you wouldn't be able to turn properly, so that is why a limited slip has its drawbacks. If the clutches are worn out, the differential acts just like a standard one where the power always takes the easiest path, so both wheels are powered if they have even resistance, but if one is held, the power goes to the other one because it causes the spider gears to walk around the axle side gears.

 

Thanks for taking the time to explain this. When I put the 26" tires on my quad it really exagerated the amount of 3wd I have. So what do I do to regain the new 4wd ability I am now missing?
Here's a question for ya- On the yamahas that have the 2wd/4wd option, is it still wearing out the clutches when riding in 2wd? Or is it preserving them for when their needed?

 

Tree Farmer, You seem to know your drivetrain. Well I developed a problem this weekend riding and I'm looking for opinion/thoughts. I was stuck in a mudhole, already in 4x4 (low) I pulled the lock and then accelerated (spinning) I was hung up on the skid trying to climb out of the mudhole. Didn't look at the speedo but would guess wheels were doing 30mph then all of a sudden a horrible grinding noise in the front diffy erupted. I winched it out, found that in 4x4 High seemed fine, going into low in 4x4 the noise and slipping returns. The front diffy does not seem to engage at all. Driving in 2x is fine accept upon letting off the gas, a lighter grinding noise starts. Like the front diffy is partially engaging. I haven't pulled anything to look yet, first thing I intend to do is drop the plug and see what comes out. Any initial thoughts though? Would you most likely say diffy damage or transfer/shaft damage? I know its just assuming right now. But reading this thread, I guess its possible while I had all tires spinning 30mph, the front could have suddenly grabbed dirt and spun out the front diffy, or its also possible I partially let go of the lock lever and it slipped out and ground something. Is it bad to let go of the lock while spinning at high speed with little or no traction?

Thanks! for any thoughts...

 

oh,
I need to specify, my "grinding" noise is actually a gears stripping/slipping sound, not really a "grinding" noise like bad bearings or somethign.