I have a 98 F150 with an 8.8 open diff that I installed a Powertraxx unit in about 6 months ago. When I heard the crunching and rattling sounds coming from the rear I knew something was wrong. When I pulled the diff cover the Powertraxx unit was perfect - the bearings on the driver side of the carrier were gone. After much cursing, grunting and sweating I got the carrier out, replaced the bearing and am about to complete re-install.
Two questions: 1) Has anyone else run into problems with Powertraxx causing bearings to go bad? 2) Has anyone else heard of the carrier bearing going bad on a truck with less than 100K miles on it?
(NOTE: Ford has "re-parted" the spacers used to align the carrier with the pinion gear, so if you have to do this don't expect to new part to have the same I.D. as the old part. The parts guy at the dealer did not know this, so this fix could have been completed last weekend instead of next weekend.)

 

All I can tell you is that I have a Powertrax No-Slip installed and I am about to do a re-install myself. In my case, the carrier shims are way out of wack and it's just a matter of time before the bearings fail as a result. I just purchased a Genuine Gear master kit and will use a caliper when choosing the correct shims.

 

Thanks for the info. I will be MUCH more sensitive to any strange noises after this last episode. (BTW - as a computer geek I am in WAY over my head already so this has been interesting.)
How will you determine what size spacer you will need? (I know you said you'd use the calipers but how are you going to determine proper carrier alignment?)

 

Thumb through this and look for backlash and carrier bearing preload.

www.ring-pinion.com/tech/yukoninst.pdf

 

Well since I'm not changing anything, and only replaceing parts, I'm going to cross my fingers and hope the shims in there now are of the right thinkness and just replace them with new identical ones. This assumption might be a mistake but I have no documentation on exactly what specs I need.