2500HD D/A rear end problem/noise

davem42 · February 26, 2007

I have a 2006 2500HD with the D/A option. At 40,600 miles the rear-end starting making a very loud noise. In an attempt to track the noise down, I inspected the rear end and there were no visible signs of a problem. My next stop was to my Chevy local dealer for repairs. They found that the smaller of the two pinion bearings had been starved of oil and had be come so hot it had "welded' it's self together. The dealer replaced both the pinion bearings and the load washer between them at no charge and no hassle from me. When I got the truck back and drove home, it sounded as if a rear door was open, it's a crew cab. So when I got home, I checked the doors and they were closed, so I drove it around the block and listen more carefully to what I was hearing. This time I realized that what I was hearing was the distinctive sound of metal on metal, as if a brake was dragging, but on application of the brakes there was no change to the noise, so I took it back to the dealer. On the second trip, the technician said he did not hear any abnormal noise, so I went back to the dealer and took a ride with the service manager. He also heard the noise but said it was normal, but I insisted that it is not “normal” and was not there before the problem with the pinion bearing. The service manager confirmed the lash was set with the service technician (but not in front of me) so the noise could not possible be coming form the pinion gear bearings of the ring and pinion gears. Since I had to make a trip in the truck he suggested that drive the truck and see if there is any thing that varies the sound. So for a 4 hour round trip I listen to the noise, varying speed, coasting up hills, down hills, doing anything I could to see if there was a change in pitch, loudness, anything to the sound. No change. If I can not help to narrow down where the problem is, the service manager suggested installing chassis ears to help pin point the problem.

To me the noise sounds like a bad bearing(s). I’ve heard many on the farm. As bad as the small pinion bearing was chewed up, it would seem to me that there are other bearings in the rear end that could have been damaged should have been inspected and replaced. So my question is this, with a failure such as the one I experienced, could my assumption about additional bad bearings be correct?

davem42 · March 15, 2007

UPDATE 3/15/2007

I took my truck to another dealer for a second opinion, bigger dealer also sells medium size trucks. They heard the noise right off, "it sounded like a freight train coming at you" was what they told me. They opened the rear end and found "large metal shavings". A tear down reviled that the pinion and side bearings were noisy, the preload was very high, a broken yoke, and no backlash was set. They replace yoke, several bearings, and races set the backlash, and filled with clean fluid. I have my old tuck back, the noise is gone, and I am a satisfied Chevy customer. I can not believe the difference in dealer service centers and philosophy. From now on the 2500HD goes the dealer here who deals with the larger trucks.