Originally Posted by Travis873o
your zj's have limited slip?
thought only the wj's and the 5.9s had limited slip
You are correct, but as stated in the FSM... "Lubricant for Model 35 axle with Trailer Tow and Trac-Lok: SAE 75W-140 SYNTHETIC gear lubricant with friction modifier."
Which, when i looked through the local stores the only gear lubes that had those specs were the LS specifc lubes. So that was my mistake. I just re-read my post and realized that i said it was LS additive, not friction modifier. I had just been talking with my buddy about his LS axle and was still in that mode of think.
But, as to the OP, when i brought it in to the shop thinking it was a more serious problem they popped the diff cover off and let the fluid drain out and could tell there was no friction modifier in it. They replaced the fluid and put in the friction modifier, no more groaning/vibration. That was my issue, hopefully thats yours too cause its a cheap fix.