Noise and vibration

msanderford

I have a 2004 chevy 2500hd 4x4 long bed. If I have weight in the back it vibrates and has noise above 55mph.. the noise goes away if I let off of the gas, if I am going up a hill or hit a dip or bump in the road it gets louder and it vibrates more. The dealer ship has had it 4 times, it is still under bumper to bumper. any sugestions

Mr_Shiftright

Vibration issues can be tough to solve, and it will probably take more than a few tries. The usual suspects are tire balance, bent wheel, frozen or loose u-joints, loose exhaust system, motor or transmission mounts. Most dealers hate chasing vibration issues to begin with, as warranty compensation is small or non-existent. You may have to resort to paying for an independent shop to track this down, as the dealers generally aren't very motivated to chasing vibration ghosts.

Hopefully, the dealer will stumble upon something obvious sooner or later. It's possible their efforts have only been half-hearted, since in addition to getting stiffed on warranty from the factory, they have to send a technician out on the road---which also makes the technician generally unhappy if he's working flat rate.

Sometimes getting the truck on a lift and running it reveals the problem.

msanderford

I have put new good tires on it, they (Chevy Dealership) replaced the motor mounts and transmission mount, replaced bearings, seals and my warrenty is and will cover it all. The mechanic Mike has went on a ride along and he has verified that there is something definitely not right with the truck. I get a loaner every time they have my truck. They are not in a hurry to work on it. It seems to me that having weight in the bed lowers and changes the pivot point of the drive shaft. It only makes the noise and vibration when I have a medium load and am accelerating above 55. It also gets louder on a hill, a dip or a bump, and the noise is in conjunction with the back bouncing up and down. If I let off of the pedal the noise and vibration stops immediately. There is a lot of play at the center shaft bearing. They say that is normal.

Mr_Shiftright

Well that's a lot more info to think about. Hmm.....the problem with the driveshaft theory is that usually driveshaft balance issues occur right at take-off speeds.

Have the u-joints been examined carefully?

msanderford

I dont know about carefully. I will check that