Motive Gear Pinion Bearing shot in less than 500 miles; did the shop mess up?

Hey guys,

I took my 2000 xj in a couple months back and had my front and rear axles regeared to 4.56. I bought all motive gear parts (ring and pinion, bearing and install kit). I had this done professionally at a shop and in less than 500 miles (closer to 300 honestly) my rear diff is howling like crazy. I jacked her up and disconnected the driveshaft and turned the pinion bearing (where the driveshaft connects to the diff) and I can feel grinding and it is just completely unsmooth.

I am presuming the shop had an excessive preload on the pinion and it just beat the shit out of the bearing but I wanted to see if anyone else had ever had a similar experience. I just think that regardless of what bearing is put in it should last a HELL of a Longer than that if installed correctly.

The shop did not originally warranty the work because I provided the parts but I am trying to get a feel for how possible it is that this is simply a parts failure and not a install error.
Any tips, advice, confirmations, or exoeriences would be appreciated.

Thanks

I don't understand why so many people try to cheap out on gear installs and void the install warranty by supplying their own parts.

Its almost guaranteed to be installer and not parts, but since you provided the parts, you're probably 100% on the hook for it.

What axle is it?

Most likely install, however I have seen bearings in proper setups go south quickly because the brand new bearing was bad. Too much preload, improper lubrication, bad bearing. There are a lot of reasons. Heck, we had a guy bring a Toyota back into the shop because his couple-hundred-mile-old r&p was howling - when we drained it we got about a quart of water out of it, before the oil came out. I would chalk that up to user error.

I agree with DiedelSJ. I've been doing gear installs for 11yrs and the shop I'm at is a Timken bearing distributor. I've seen a few Timken bearings fail too early also. My favorite is explaining the break in procedure with customers, then they proceed to destroy the gear in a few days.

Yup. New means new, not always "good". Where in the springs did you take it?