2005 Chevrolet Avalanche • V8 2WD Automatic • 65,000 miles

This appears to happen only when the truck is cold.
About 10 minutes after you get on the freeway
60 to 70 mph the front end starts to shake steering wheel also. The longer you drive at a steady speed the worse it gets. Step on the brakes it gets worse. Take your foot off the gas and let the truck slow down 20 to 30 mph the shake stops. Now when you speed up again to 60 mph or more the shake DOES NOT COME BACK. You can drive all day long at freeway speeds and no shake at all perfect ride. Park the truck for 4hrs or more and it all starts over again.
Got any ideas Please help if you can.
December 11, 2010.

I would start with an alignment and check the front end components.

Also move front tires to rear, if shaking stops, then tires are problem.

Dec 11, 2010.
I agree with mmprince with getting the alignment and getting the front end checked, often with tyre problems, if front steering is affected by the vibration, rear is normally only felt in the body as a vibration with little effect on the steering.

Mark (mhpautos)

Dec 11, 2010.