ok guys, just checking here, picked up my first jeep not long ago 97 grand 4.0l auto, i want to (later on after coming back from France in the summer) do a 4" lift on her, but at the moment i have one thing to fix, on driving her back i noticed i had a low pitched whine coming from the rear, i have only checked the wheels bearings on the ground at the moment, (not jacked) but they did seem ok.
its a sort of low pitched whine that seems to get higher the faster i drive but that may of course just be a speed thing, i am going to tomorrow, drain the diff and put new oil in to see if that does it, is the additive really necessary *** i cant get it here for about a week after i have put the new oil in, is that ok? or i have other additive in the garage (prolong) which i always use in the engine.
any other things i could look for, or the noise could be?

 

here ya go bud hope it helps. same problem im having

https://www.cherokeeforum.com/f5/cre...nd-rear-47468/

 

Just check first and make sure your rear axle isnt low on fluid.

 

x91j, i think we are having different probs, from your vids yours is like a creak/squeak, wine is a constant lower whine, no clunking clicking etc, and the wheels run fine, i suspect its a bearing/oil chang diff thing, could of course be wrong, thanks for the link though, going on, is it ok if i dont put additive in straight away if i cant get it, (within a week) or is that lucas one ok as is? what weight should i use?