Newbie here. I recently purchased a 1998 Chevy extended-cab C1500 5.7l 2wd truck. I got it cheap and it has some issues. The top of the list is a vibration that starts around 30mph and gets fairly bad at highway speeds. All of the tires are fairly new and have been balanced and I have had the steering rebuilt (new pitman and idler arm) because it was loose. I just repacked the front bearings and put on new brake pads so the front is now in good shape. The vibration is not in the wheel but all over. I am thinking drivetrain and the drive shaft does have some movement at the center carrier bearing. Could this be my issue or just a symptom? Driveshaft out of balance maybe? U-Joints?

Reading through some posts on this board I see that most of this truck's problems are in the "common issues" post, lol. The previous owners did not give it much TLC.

If you are wondering about my screen name, I am all over the LSx car boards with my Camaro and decided to just use the same name here.

 

Well the carrier bearing will have some play, but what you wanna look for is the rubber is intact. When they go bad, the rubber seperates from the bearing or housing. A simple move up and down gives a quick check. As far as driveshaft balance, the way I check is get on the highway, take off like normal and get up to bout 70. Then let off the throttle and see if the vibration goes away. This does not guarantee a way confirm it is, but thats a quick way to narrow it down. New u joints can even throw the balance off sometimes.

 

Thanks for the reply. I can see that the rubber around the bearing is cracked. The vibration does not stop until I am back down to 10mph or so.

 

Has it been lifted or lowered? Does it have wheel spacers?

 

Everything is stock except for the cheap "custom" 15" wheels.

 

Well you might check for wheel spacers. If they are installed wrong, this causes a constant vibration.