Rear end noise.
 

I have a 97 Cherokee Sport with 3" lift on 31's. It has the chrystler rear end. I have a weird noise coming from the rear end. Most of the time when driving, if i let off of the gas and coast it makes a weird "wah" noise or like a grinding type noise, its really hard to explain. It doesn't it doing constantly it will do it off and on. At lower speeds it doesn't do it when accelerating but when driving on the interstate today it seemed like it was doing it a little while crusing at 75.
I am planning on changing the differential fluid this weekend but was wondering anyone knew what the issue may be incase its something i could fix while i have the diff cover off.

Also is there any part of rear end to check when changing the differential fluid?

Thanks!

Rear end noise.
 

It could be any of the bearings in the rear end, or it could be rear brakes. Does the noise change at all when you hit the brakes?

I don't remember for sure. It kind of seems like it either quiets down or stops when your hit the brakes and the gas. I know for sure when you are on the gas it does stop.

Not much you can do with the cover off, other than look for ecessive wear on gears.
Most anything else is very involved. You could check pinion for excess slop (up/down) with/withoit cover off. Check drive shaft joints for slop, maybe even take it off and see if joints have smooth operation, not "notchy" or stiff. Might as well check (or change) TC fluid. Sure couldn't hurt, that is unless you know when it was done last.

Ok so i Changed the diff fluid today. I cleaned out the inside and replaced it with new fluid. The noise may have quieted down a very small amount but it still there. Any ideas?

Attachment 315483
before

Attachment 315484
after

I did notice one thing when changing. if i moved the wheel back and fourth the small gear at the top of the pin has some play in it. Is that normal?

Attachment 315485
thats the piece with some play.