Vibrationn at 35-40 MPH
 

I get a strange vibration between 35-40 MPH when I am accelerating but it stops when I back off the gas pedal. 2001 GMC SWB 2x2 Stepside with auto V6. The front end does not vibrate and the noise stops above 40 MPH. Could it be the drive line? Any suggestions?

Re: Vibrationn at 35-40 MPH
 

balance tires and check for front end play and see if the tires are chopped

Re: Vibrationn at 35-40 MPH
 

Tire balance, tire out of round (belt separation?), bent wheel, front end wear, driveshaft universal joint, ----could be any of the above. Go for the simple first.

Re: Vibrationn at 35-40 MPH
 

I had a rear end that had an improper set up and was in dire need of a rebuild that would cause the truck to vibrate while decelerating from highway speeds.

Re: Vibrationn at 35-40 MPH
 

From your description I would lean towards driveline. U-joints would be my first choice. Pull shaft and fell if joints are binding. If joints are smooth then I might ask you if the tune up and or plug wires has ever been performed (replaced?) Maybe it is misfiring on acceleration.

Re: Vibrationn at 35-40 MPH
 

Look at your U-joints first, then look at tires and see if you threw a weight off of abalance spot or have a tire that is demonstrating a busted belt.

Re: Vibrationn at 35-40 MPH
 

I just put on 4 new tires and wheels off of a 2008 GMC Yukon. The issue is still there. I suspect the DL. I will check that out next.

Thanks for the help!