So apparently my truck (08 xlt with xtr package) has a 3.55 limited slip axle.
I thought id test for the first time, how this works, so i found a patch of ice and drove on it so one side of the truck was on the icey side and the other side in direct contact with the pavement. Then in 2wd I gave it enough gas and the right side which was on the icey part, just kept spinning without the left side that was on the pavement engaging. I also did it on the opposite side and in reverse but the part that was on the ice just kept spinning. Am I doing something wrong? Is the limited slip thing not working/broken? Or did my dealer bullish me about the lsd and charge me for it anyway? Or maybe I just don't fully understand how drivetrains work and limited slip diffs are different from limited slip axles.
Sorry if its a noob question hehe

 

Here is a quote that help me understand, I literally had the exact same question when I joined this forum





Factory LSD uses a series of clutch discs that will lose their efficiency over time. Depending on how many miles are on your truck and how well the rear end was maintained, it will determine how much slip is going to happen. Because its "limited" slip, its still going to allow the other wheel to slip a lot...but it will still transfer a small portion of power to that wheel to at least get you moving. A factory LSD rear end in good working condition might transfer 25-35 percent of available power to your non slipping tire...but thats really in a perfect world. If you find your stuck, put the truck in 2nd and SLOWLY apply power...just stomping on it is going to overpower the LSD and like you discovered, you will just spin the one, no traction tire. Doing a burn out on pavement where you have good traction to both tires will get you much closer to a 50\50 power distribution to both tires...again, as you discovered.

If you want both wheels to spin at the same speed, all the time, get a locker....but it will eat rear tires much faster and your street driving manners will drop off sharply unless you get a selectable locker(ARB, etc).



If you go to my profile and search all the threads I have started at the beginning you will see a thread I started about the same thing, some good info on it

 

Thanks that quote pretty much cleared it up for me. I think i might do some research on one and invest in a locker. Plus my truck only has 49000kms of easy life on it and the limited slip is already pooched. Kind of a downer oh well

 

look into getting a gear driven lsd too, don't wear out like clutch style and are much more useful for the street than a locker. Also, Diff's are the part inside axles that turn the wheels, so no matter what kind of axle you have, it will have a diff inside of it

 

even with brand knew clutch plate..the force needed to be apply to have them "unlocked" is about 25 ft/lbs which is about nothing.

When I busted the spider gear on my ex ranger cause of the clutch were totally worn out (120K miles) I set then real tight and the best I could acheived was about 40ft/lbs.

this kind of limited slip is the ****tier one. :| but it still help in snow..but you need to be gentle on the gas..if not: it's totally useless.

 

Limited slips also have a down fall of when one tire has zero traction or near zero traction all torque goes to that tire. Like if one tire is in the air or one tire is on slick ice it would get 100% of the torque. This is why most hardcore offroad veh. have lockers.

As stated above if you go with a automatic locker-lunch box locker-etc you will have a noisy rearend as it locks and unlocks but will give you 50/50 all the time. A selectable locker will run you much more but you have control as to when it locks up and unlocks so you have more drivable rearend day to day but have the option of full locking axle when needed.

Here is a link that describes how differentials work if your curious...
http://therangerstation.com/Magazine/Feb%2006/tech.htm

 

The Detroit Tru-trac is an awesome unit, far better than the factory LSD and it isn't clutch driven so it won't wear out. You also don't get the constant tire chirp on the pavement like with a locker.