got a vibration starts around 55mph gets worse around 65mph then lessons at 70-75mph....its got new u-joints and the whole drive shaft has been balanced twice, it also has a new carrier bearing but I was told that it was a cheap version. Another odd thing is that when its cold out the vibration seems to be nonexistant until the drivetrain gets warmed up. I have come to the conclusion that its the carrier bearing...but wanted to check with the experts before I take the driveshaft back out again.

thanks

ive got the same darn problem and I have new u-joints and carrier as well. mine is the worst at 30-35mph and clears up after that.

maybe it is the tranny (auto) mount or pinion bearing, I don't know but I can stand to drive it right now. :mad3:

the carrier bearing isn't moved over to one side or the other is it? I worked on one for a guy awhile back that was shoved to one side. I put the spare set of drivelines for my dually into it to check that idea out the vibe was still there recentered the old set went away. Has the truck been lowered any in the rear? My old one done that after we lowered it, had to space the carrier bearing down some.

its in the stock location and stock suspension as far as I can tell.

A carrier usually makes noise rather than cause vibration doesn't it? :confused:

I dunno :p

Have you tried flipping the drive shaft around? Did U-joints in a camaro and put the drive shaft in and it had a vibration...so I flipped it around and it fixed it.
Have you had the drive shaft balanced by the same shop or did you take it to two different shops?

haven't tried flipping it, don't know if that is possible since it has the carrier bearing.....same shop balanced it but they are very reputable so I'm farely sure the its balanced right. Keep em coming, someone will come up with the right answer!!!

last night I noticed on mine that the spacers between the carrier and mount are gone!! when I bought this truck, I wanted it all new underneath and took it and had the new carrier put in. It had about a 1/2" spacer on it and now its mounted flush... im thinking this might have something to do with it.?

maybe someone can check their LB Dually Crew Cab to see if there is a spacer, I know mine doesn't have them either.

haven't tried flipping it, don't know if that is possible since it has the carrier bearing

http://www.bluefox.tv/~iroc/bonk.gif
Sorry...it's been a long week. :D

Did it vibrate like it does before you replaced the carrier and u-joints?

Did you use a press on the carrier or did you beat it out when you replaced it?

I bought the truck with the new carrier on it and balanced. It had a vibration so I took it off and took it back to Power Drive Inc and they told me that the carrier was a cheapo, then they rebalanced it. Still have the vibration though.

have you swaped the tires around yet?, to see if it transmitting back up through the drive line, sounds to me like it could be a bad tire. usually the drive line vibs get sent straight to the seat of your pants , but are very weak. if its a stronger vibration then it would be coming from something with more mass like a tire.
if you can, do the tire thing before you spend alot of money chasing it.