I’ve had my Jeep cherokee sport rear diff. rebuilt by a local shop and it is still making the typical “whirring” sound from the rear. The shop took it apart twice, replaced the bearings and it still isnt fixed! Now there saying the whole rear axle housing is probably warped due to possible overheating and is causing the bearings to wear out and needs to be replaced. I’ve spent $2,500 already! Help! Has anybody heard of such a thing or is this a bunch of bull?
I’m ready to get a second opinion from another shop and get ready to go to small claims court if necessary.
The only thing that should cause any overheating would be lack of lubricant (as in a major leak) or if the ring and pinion gear were not set up properly.
Offhand, I’d say it sounds like BS. Setting up a rear axle is a pretty technical job and can easily go awry if extreme care is not used.
Wonder what they would say if you asked a question about magnetic base dial indicators… 
VERY few mechanics / shops have the tools and ability to properly set up a rear end…Very few 1998 Jeeps ever NEED to have their axles rebuilt…Personally, I would prefer a good USED factory rear axle assembly if needed than trying to rebuild one in the field…
The ring and pinion gears are a matched pair. They must be replaced as a matched pair and very carefully installed and set up. The pinion bearings are shimmed (to get the proper fit) and then pre-loaded, sometimes using a part called a crush-sleeve. One little assembly error and it’s going to howl like a banshee… This is a job for highly paid specialists…Since they seldom fail, they are readily available in salvage yards. Be sure to get the correct gear ratio for your vehicle…
I went to the junkyard and bought a replacement axle for $50, put it in (in my apt. parking lot) in 3 hours. No need to ever rebuild one, unless it’s extremely rare.
It would be interesting to see the invoice on the repair. Early 90s models had a problem with carrier bearings it seems but with the tools needed to set the pre-load and mesh it was not difficult. I do not recall ever getting any deeper into a Jeep rear axle and I have owned and worked on many. In fact, when rear end work required replacing the ring and pinion I farmed them out to a competitor who specialized in axle work or, if available, bought a used part as already suggested. For the DIY that certainly is the best plan.
Thanks for the comments. The shop did replace the ring & pinion gears/carrier also which they said should’ve fixed the problem but didnt. My opinion is this shop is incompetant and I will be taking them to small claims.
Sounds like replacing the rear end with a used one from the junkyard was the way I should’ve went in the first place. Replacing the rear end myself is not an option as it is beyond my skills. I am not a DIY except for oil changes, fluid checks etc.
Thanks