Odd vibration at low speeds

[TahoeInFC]

I've heard the U-joints can do this. I don't think they've ever been replaced in this thing, so all of them have about 122k on them. I'll crawl around under there this weekend and try the temporary shimming on the heat shield.
Will also have a look at the U-joints to see if they have extra play or show signs of wear.
Thanks.

 

[1998Suburban]

My u-joints all checked out ok and the fronts were relatively new. It was only after I pulled the front d/s out to replace them that I found the problem. With the D/S on the ground one U joint was binding up in one direction.

 

[TahoeInFC]

Alright folks, I finally had the chance to crawl under the truck with some tools and a flashlight this past weekend. I Tightened the screws that hold the heat shield (opposite side of the firewall as the gas pedal) to the body, and lo and behold the buzzing stopped cold. I think it was just picking up exhaust vibrations from the driver's side pipes, which pass about 2" away from this shield. Gradually, over 17 years, the shield loosened up.
No more irritating vibrations! Sometimes the fix is simple and cheap, and other times, well...

Thanks for all your help!

 

[1998Suburban]

Glad you found the problem. The fact that it was an easy fix is a great bonus