Sooo... Let me start with, I have a 97' XJ, with 215,000 miles on it. I put a 4.5" lift on it and up sized to 33" tires. Also a new CV drive shaft, and degree shimmed the pumpkin for a shallower angle. Next logical step was a re-gear.
I have a manual 5 speed, so decided to gear to 4.10's. I took my jeep to Desert Rat, and they did the work. i had the jeep back about a week, and after following the proper break in procedures, I took it on the freeway (after the 100mile mark) and the rear end started to whine. Called and got my jeep back in. They said a bearing had gone out, and of course tore up the pinion and ring gear. They did it again, and this time I got my jeep back and the same whine came back before I had even gotten home. Called, took the jeep back. This time they re-geared with Yukon (not sure what they used the first time). Gears lasted less that 10 miles before same whine. The gears had been good for 215,000miles so obviously something changed/was ruined with the first re-gear. SO, desert rat replaced my rear axle (at no charge to me) and geared again. I had them put a locker in this time since they were in there. This time the gear break in was going great. Slow break in till 100 miles, then gradually more speed, faster takes offs, etc. Then today (after mile 220 or so) I was on the freeway today, about 75mph, for less that 10 mins and the whine started back up...
Does ANYONE have any clue what is going on or have any advice to offer??
I have an appt to take the jeep back again, but I don't want them to just keep throwing parts at it if there is something were all overlooking....

 

Sounds like you should get your money back and take it to another shop?

 

^that.

I have never had an issue like that on the gears I installed. Sounds like they don't understand preload.

 

X3...have them refund your money and find a different shop

 

Sounds like they need to learn how to do a crush sleeve.

 

Are you 100% sure that the slinger is installed between the pinion head and inner bearing?
Is there a baffle installed under the inner bearing race?

 

They may not know what they are doing but at least they stand behind there work.

 

Very true. Gotta commend them on that.

 

the 8.25 is a bit tricky to set up properly.... BUT, i dont think they know what they are doing. find another shop ASAP. I have 265 K on my 98 and the rear was still in great shape and quiet, I re-geared when I installed my Ox Locker my first attempt i got it so close to dead on that I thought i would be ok... NOPE. noisy, so i took it to a shop here where i live that was known for doing great Dif work, an hour or so later it was done and has been perfect ever since.

 

I will agree on that...it is costing them a pretty penny though...IF they are truly using new parts every time

 

Yeah, something is really wonky (I assume they are not setting it up right). For reference, I regeared my Ford 8.8 in my Mustang and put 800hp to it after about 25 miles. Holding up just fine after countless V-max runs and hard launches.

 

my main ideas as to why this is happening are that
1) the preload isnt correct.... either on the pinion bearings or carrier bearings, maybe both.
2) the 'C' clamps that hold the splines that move the carrier group back and fourth, and hold the carrier bearing race isn't being tightened down enough, so it gives the race room to spin inside the clip.
3) the crush sleeve is possibly being over tightened, causing it to fail after X number of miles, and then loosing the pinion bearing preload.

Do these sound possible to any of the gear guys out there? It's weird that it would be happening over and over and over.
The store manager has had all 3 of the gear tech's look at the diff... Seems like not all 3 would continue to mess it up.

 

I'd go with crush sleeve. Took me 3 to get mine right...

I don't think the adjuster locks need a million pounds of torque, mine haven't at least. I used red locktite.