Odd noise/vibration off throttle at HW speeds...

[RobK]

Hey guys, I'm experiencing a weird "rumble" and vibration in my '98 Suburban that's got me stumped. Cruising between 60 and 70 I notice a considerable rumble and vibration through the entire truck (and steering wheel) whenever I lift of the throttle. As soon as I get back in it the sound and vibration go away. It doesn't seem to be engine/tranny related because there was no change when I slipped it down to third or even into neutral. It's barely noticeable below sixty and seems worst at about 70. The only thing I've changed in the recent past is I bumped up the tire pressures to the "normal" recommendation rather than the "comfort" pressures. Since it seems directly related to road speed and isn't dependant on engine speed, I'm guessing a u-joint or something along those lines. Any ideas???

Thanks!
Rob K.

BTW- Gotta love the Kennedy quick heat plugs when it's -5 deg. out! My truck starts better now than it EVER did!

[rapidoxidationman]

A u-joint would be my first guess. You can crawl under the truck and start trying to wiggle the drive shafts; any play in any u-joint is not acceptable.
Good luck!
Rapid