[Jim 06]

just bought an 06 grand Cherokee. it has a. a noisy rear diff. does anyone have suggestions on how to fix it. ring and pinion were changed and removed didn't help. dealers here want $140 to look at it they are no help.

 

[Gearman]

First, I would be sure to pinpoint where your "noise" is coming from and describe the noise here to the other members. That way you have a better chance of not replacing parts needlessly. Case in point, I had a condition a few years back on my 2005 making a Creaking / ticking / ringing sound at the rear end while in drive. It turned out to be the U-Joint on the drive shaft in the back which in the case of the stock drive shaft cannot be replaced and required a new unit. I had visited with the local stealership and the service representative told me they had diagnosed I had a differential issue after a short drive.

The way I checked this at home was I jack up the vehicle front & rear on level ground and set it on jack stands with the tires slightly off the ground. Then I started the engine let it warm up until it reached low stable idle. Then I put in in drive, (do not accelerate at any time as you can damage your drive train), I slid underneath in back with a mechanics stethoscope and used that and my normal hearing to pinpoint the noise.

I cannot be sure that this will work for you, but it is something you can try. Good luck and keep the members updated as you find your fix. I could help someone else out.

 

[Seakir]

Check tyre pressures first before doing anything- as long as they're OK and you still have a noise, then proceed. My wj whines when the rear left tyre drops to 19 psi due to the pot holes and crappy curb corners we have.
Crap roads also make whines, and some road surfaces are designed to make tyres whine over certain speeds in order to irritate drivers and make them slow down.

 

[dmsfun]

Hello and welcome to the forum. The most likely issue is the carrier bearing is going bad in the rear diff. All the bearings will need to be replaced, since particles from the bad one are circulating in the fluid. I've had to have 2 rear diff bearing kits put in my 06 since new, once under warranty. The cost is close to 1k, mostly labor charge.