So Ive got a vibe at 70mph and worse at 75, keeps on the faster I go.

98 QC 3500, 5 speed.
All ujoints are tight.
front locking hubs, so nothing up front should be spinning anyway
pretty new tires, but did it with the old baldy's too

Checked wheel bearings, everything's happy there. Vibe didnt change when the front hubs went on, (hoping a toasted unit bearing)

So only thing left is the carrier bearing, which looks like its sagged out in its rubber mount. Truck has a bit over 260k on it, so I wouldnt be surprised. Only other thing, is there is some play in the slip in the back of the tcase, but very very minimal, and no leaking.

Any other ideas?

 

grab the diveshaft right next to the bearing and give it a few good jerks while watching the rubber, if it moves more then ¼" then it is bad

 

With those miles you got more then your money's worth out a that thing. I'd change it just for the sake of changing it myself. They aren't expensive and not all that hard to change.

The vibe could also be tires out of balance or one going bad.

 

Identical with old tires, and new tires, and even rotoraed around. Nothing the in the steering at all.

I cant come uo with anything else, so it looks like that will be the method "throw money at it"

 

Driveshaft may also be out of balance if one of the weights fell off or somethin like that. If the driveshaft has ever been off they may have put it back on off balance also.

I just changed this carrier bearing a few months back and as a word of warning, the one I got from both Auto Zone and Napa didn't fit. I got the right size from Oriely's. So check it before you tear it apart if this is your only transport.

 

Yea what he said, they only make about three differnt styles for a 5 speed.