Can you give me a few ideas to investigate? 2002-1/2t HD-crew cab-6.0-90k. Tires have 9k on. I have a bad vibration @ 45 mph I think is coming from the rear as pass. seat shakes bad. Had tires balanced twice in 100 miles. Had spare balanced, put spare on each wheel, 1 at a time, went for ride and made no diff. in the vibration. Blocked it up, ran in low, checked u-joints, carrier bearing and rear wheel bearings and all look good. Checked all tires for out of round. Need some more ideas please. woody

 

Bent rim, bent axle, broken radial belt, thrown wheel weight as i had brand new tires put on just recently and threw a weight almost immediately. Those are my suggestions.

 

Possible bent driveshaft maybe? I have also had a bad shock cause a vibration believe it or not.

 

Could the drive shaft simply just be out of balance or have thrown a weight?

 

Very possible...you could also have something in the transmission that is not right or even the flywheel.

Are you sure your tire guy is giving you a high speed balance and not using one of those old fashioned manual balancers? I got tires at Tire Kingdom and had a BAD vibration. I took it back and they said all was well...vibration was still there. I had to get a little nasty with them and they checked it one more time in front of me. The dumbass mechanic didn't bother balancing the rear wheels. He said he never does. Lazy *** bastard! After he did - guess what - no more vibration.

 

Woodman,Inspect your driveline as mententioned above, and your u-joints for wear.Now look at the yoke that goes into the transmission and attaches to the driveline. You may find a Harmonic Balancer on the yoke. If you have one it most likely has gone bad and is causing this vibration.Bad news is they do not make them anymore, which means that you have to buy a new yoke and have your driveline rebalanced.If you can afford the down time on your truck there are some places that rebuild harmonic balancers. Just Google harmonic balancers and you can locate them. I do not know if they rebuild them on the yoke.I replaced my yoke and had my driveline rebalanced and the problem was solved.jvp

 

I thank everyone for responding. I'm going to take the truck to a new tire place and get that second opinion. Next step will be to get the truck on a rack so it can be inspected from end to end. I think my local "old fashioned" service station will do it for me. I will be back on here in a couple weeks with the results. GM people are the best!!! woody

 

have you check front rotor run out

 

Check your rear drive shaft. One end is capped off and the other end is open, if it isn't put on correctly. It will hold water.

Atleast thats what happened to a friend of mine when he was launching his boat, truck was half under water though. Not sure if urs is the same type/style of drive shaft or if they are sealing both ends now... dunno

hope this helps

 

To all of you that gave me ideas to investigate, I want to thank you. Finally took the 02 to a Chevy Dealer in Missouri. They have a "Road Force" spin balancer. The mechanic called me to come back to his bay to see what he found. When applying the road force, my tires registered readings from 26 to 60. According to him, they should read in the very low teens. I'm sure there are several of you on the forum that know what he was explaining to me. I could actually see the in and out, up and down wobble in the tires while spinning with the road force applied. Dealer gave me new set for 1/2 price. Thanks again. Mission accomplished!