I have a 2000 Express 3500 with 193K miles. I just purchased the vehicle so I do not know the history or when this started. At about 50 mph the entire vehicle vibrates like you are driving over rumble strips on the road. Over 55mph it starts to go away and at 60mph it is smooth.

It is in the shop to get the wheels balanced today, but I have a feeling it won't be that simple.

One thing I tried was putting the vehicle into neutral while coming down a hill to help determine if it was engine related. The vibration remained unchanged when in neutral.

Any ideas?

 

sounds like a tire balance issue to me

 

Yep I agree. It will just be a wheel balance issue.

 

Its always a good idea to get under the vehicle and inspect for any debris wrapped around the drive shaft or caught up in the wheel... I know its rare but it can happen....

 

Sounds like a typical tire problem.

 

Had same problem in older van turn out i had to have the drive shaft rebalanced

 

it might be a driveshaft if the vibration was constant but when its in a speed zone it might be unbalanced wheels in both of my G30's i found that they were picky about old tires fighting new ones also how long did the vehicle sit, if you burn out the tires can rotate on the rim causing vibration, anti-sway bar bushings.

 

I have had the same problem with a couple vehicles I have owned. In both cases it was a driveline balance issue. Check the u-joints and the steady bearing.
From my eperience a tire balance problem will not go away as speed increases.
Any play in a u-joint and it is worn out, a u-joint can dry out and seize causing problems too.
At that mileage it might not hurt to replace the u-joints and steady bearing as a precaution.

Terry

 

a year can and went before the 2nd post

 

they got most of the shimmy out but when you said driveline, that was it the vehicle had sat for a season in Iowa and some rust started on the bottom side where the water dripped and that little bit of rust unbalanced the driveshaft and was eatting the carrier bearing ssoooooo.... i balanced the shaft and new carrier and its like driving a brand new van