Chevy & GMC Vans

I am experiencing severe bumping whenever I drive between 65 and 74 miles per hour. Over 74 miles per hour the bumping decreases (or seems to). I have had a front end alignment and all wheels balanced. Bumping continued, mechanic replaced front routers (said they were warped) and replaced tires. Still bumping!

I am stumped. Does anyone have any idea what may be the problem?

My Van is a 1992 CL "Shorty"
RWD, 171328 Original Miles

Please post if it is a AWD or RWD and the yr of the van.BTW-welcome to the site.You might want to consider adding that info to your signature.

Worn shocks? Bad U-joint? Those are about the only things left. With the alignment, I will assume the steering components are good and tight.

I'm thinking u-joints, but it could be shocks as well.

How about rear axle bearings?

Just a guess, Jim

Thanks for filling in your vans info.Could you be more descriptive.More like it is coming from the(as a example the right front) and more than just it is bumping.Is it like a vibration from somewhat in the driveline.That will help narrow it down.


Edit:

Not sure how,but your mechanic could have missed broken or loose swap bar links.That would cause a bumping effect.

JimG wrote:I am experiencing severe bumping whenever I drive between 65 and 74 miles per hour. Over 74 miles per hour the bumping decreases (or seems to). I have had a front end alignment and all wheels balanced. Bumping continued, mechanic replaced front routers (said they were warped) and replaced tires. Still bumping!

I am stumped. Does anyone have any idea what may be the problem?

My Van is a 1992 CL "Shorty"
RWD, 171328 Original Miles

Sounds like shocks to me.

Good luck, and keep us posted with what you find.

Drive safe,

Dan Harriman 91 Safari Shorty V8 R.I.P.
Orange Texas

The location of the roughness is very difficult to pinpoint. Seems to be coming from the front.

The following things have been done in the past two weeks:

New shocks,
New rotors,
New brakes (all four weeks),
Front-end alignment,
New tires (balanced twice).

Mechanic says he checked u-joints and they are fine.

I'm driving the van tonight on a delivery route of 540 miles, and will see what happens whenever I reach a speed(70 or higher) that is difficult to achieve locally.

While driving on Monday night, I found that the (and I now believe it is more a vibration) vibration stops if making a right curve in the road and increases when making a left curve. I am thinking it is the left rear bearings. Any thoughts?

Check the tires for "out of round". Even new tires can be defective. No amount of balancing will cure an out of round condition.