Hi , I have a 2001 Jeep Cherokee with a 4.0 everything stock. My rear end was sagging badly so I replaced the rear shocks and springs. After doing this I noticed a wirrrr or grinding noise on acceleration, more after taking foot off the gas, but still there after I continue accelerating. I checked the differential oil and it was very low, after filling gear box the noise is still there. any ideas?

 

while i have not replaced mine so i dont have any experience in the area, i would guess its the simply the springs settling in.

 

May be an old u joint that is happy having its operating range changed.

 

This

 

I just had the same thing....it was the U joints. They get worn in to a spot, and don't like change.

 

Does he have to change this? Or let it settle?

 

If it's a u-joint, it needs to be replaced.

 

Took the Jeep to 1st transmission shop, they told me differential needs to be rebuilt, gears are no good $1750. Shop #2 he told me the axle tube that goes into the differential was loose and the differential gears are ok, he took it apart and epoxied the tube back in. He told me the epoxy would hold and there would be no problem. After doing this he also replaced the wheel bearing.$600. Not too sure about the epoxy, but he assured me it would be ok and that he wouldn't do it if it wasn't safe. I cant believe the ride, no more noise and no more sound like something is jumping around in the trunk. The axle tube must have been loose for a long time.

 

Do you have an XJ or a WJ?

 

This is why I have trust issues. I guess it's good that you didn't stick with the first opinion.

I'm not sure what kind of epoxy the 2nd shop would have have used (JB Weld?), but I can't say I'd feel comfortable using it to hold my axle tube in place. $600 is pretty steep for a new bearing and some Elmer's glue. I hate to be the bearer of bad news, but you could've picked up a replacement rear axle from the junkyard for around $150. Even with new brakes, bearings, etc., you'd have to try pretty hard to get close to $600.

 

He's got a WJ, aluminum housing with steel tubes.....thus the reason for epoxy.

 

Ah, I assumed XJ. Makes a little more sense.