Help!! Vibration On My GMC Savanna Van??

[tcr1016]

I have a 97 GMC Savanna Van that has a 5.7 liter motor.

 

My question is when I drive around 40-45mph, sometimes I get a vibration that seems to come from under the van. Vibrates the van like driving over the cuts they put on the white line on the right hand side of the road. I can't figure out what is causing it. I took it to a mechanic and he had no clue. It seems to be getting more frequent now. But it only does it when I drive in the 40mph range.

 

Has anyone had this problem before? I would appreciate any help you can give.

[Silverado4x4]

Sounds like the driveshaft slung a weight off (happens) have your mechanic check the driveshaft for balance. At 40 mph and up thats when the driveshaft will show its balance problem.

[tcr1016]

Thanks Elite.... But I forgot to add that if I let my foot off the gas or speed up the vibration goes away. It only does it at a constant speed in the 40mph range.

 

I this common for the driveline being off balance??

[tcr1016]

No damage at all.... I was told that it may need balanced... has anyone used the hose clamp method to balance the drivetrain? Where do I put them and how tight are they supposed to be??

[txab]

If the drive shaft needs to be balanced, remove it and take it to a driveline shop and have it done properly