Sometimes I can do a 3rd gear dump and the RR spins, and sometimes both will spin and it gets sideways. Just wondering if there is any adjustment or shimming I can do to make my diff lock up like it should. I have heard of some fluid treatment that helps limited slip diffs function properly.

 

Dealers carry an additive for the LSD but it is usually to stop chattering in the rear when cornering. It is commonly called a friction modifier.

Mine seemed to work a lot better when I switched to synthetic lube with no modifier added.

 

If your diff isn't grabbing all the time right now, don't put friction modifier in it. It will make it grab even less. There's a diagram floating around here somewhere about a different way to stack the clutches so it grabs better. Might want to do a search on it.

 

If you're going to tear into it, get a new set of clutches and redo it while you're in there. Got mine from Reider Racing. Not a hard job, but you might want help wrestling the diff in and out of the axle. Clutch packs are under $100.

 

Depending on if you are a Trac Lok or Power Lok LSD the clutch kits should be in the $60 ball park. Stacking the clutches is easy, if you want a little more bite there are a couple of threads where we have discussed how to stack them and the options w/ a Plok

 

If you are allowing one tire to spin then you are destroying your limited slip in a hurry. I cant say for sure without actually seeing your diff in action, but if you do what you just described often then your clutch packs need to be replaced. Also running two different size tires on an axle with LS will ruin the clutches in about 10 miles.