2001 z71 crunching noise at very low speeds

[ruvaugha]

At very low speeds (idle through 10 mph) I hear a crunching noise from underneath the truck. Sounds like I'm driving over a smooshed aluminum can. Noise repeats proportional to speed, but not engine rpm (doesn't occur if I gas up while in neutral). Very noticeable when going drive-thru or driving along a wall or building. My mechanic tried telling me it was gravel in my tires..I didn't believe him, but I went to the trouble of removing all rocks/gravel anyways...no success. Any ideas? Noise is driving me crazy!

[cjb321]

ujoints on the driveshaft are probably dry, the hollow aluminum shaft makes it sound like its coming from right under the cab. I just had the same problem with mine, replaced both joints on the rear shaft and its all quiet again

[ruvaugha]

ujoints on the driveshaft are probably dry, the hollow aluminum shaft makes it sound like its coming from right under the cab. I just had the same problem with mine, replaced both joints on the rear shaft and its all quiet again

Thanks for the info! Was your noise a squeal, or a crunching? I've considered u-joints, but always thought it'd be more of a squeal...

[cjb321]

mine sounded like a hamster in his wheel but all the bearings were still there just dry as a bone, possible yours is eating the bearings which could make it sound crunchy.

[ruvaugha]

good point. thanks!