Driveshaft carrier bearing noise?


Well-Known Member
Mar 20, 2005
I've got a strange noise in the Hambulance thats got me a little stumped. Heres the symptoms.

If the rig is cold you can drive around all day and never hear it. If you get up to highway speed after about 10 minutes it will turn on like a light switch. The noise it high pitched enough that I belive it's before the final gear reduction, and follows vehicle speed not engine speed. If you slow down from highway speed at an exit ramp, you'll hear it all the way down to about 25mph. If you get stopped at the light as sit for 30 seconds it won't come back at surface street speed. If you don't stop at the light, the noise continues until you stop even at low speed. Last weekend I went from Winston to Bravard and back and the noise stayed on the entire 400 miles never getting any better or worse.

I'm having trouble believing that a roller bearing noise would turn on and off so reliably in the transmission or differential. But I looked at the carrier and its not visually shot and downst have excessive radial play. Anyone ever had something like this happen?
After seeing how cheap replacement bearings are, I figured I'd give it a shot. Finished up this morning and did a 40 mile lap around town without any noise.

After unbolting the old bearing from the chassis I could feel and hear a bit of crunchiness spinning it around the shaft. Strangely however, after pressing it off, and deforming the outer race slightly in the process, the old bearing ran completely smooth.

So I have no idea what was actually going on. YMMV.