Just picked up a CTD '04 QC a little over 2 weeks ago and it now has developed some sort of vibration. It is a 305hp with the 48re and 90k miles. Ran beautifully.....wife's been driving it and I get in the other day and something just isn't right. There's a vibration....not like a wheel out of balance, but something in the drivetrain. Had the cruise set at 66 and it was quite noticable. Seemed to be a little more pronounced when pulling up the hills. Hit the brake to disengage the cruise and it stopped. Wasn't just in cruise , but whenever underpower say above 30mph and 1500rpm Anybody got any ideas? Thanks,jim

 

My 04.5 had a vibration as soon as you hit 70mph. As soon as you went a little past 70 it went away. Someware on hear thay said it had something to do with the driveline being out of balance. Oh by the way. My 06 is as smooth as silk.

 

Maybe a seizing u/joint. Have a friend with a NEW 06 4x4.It HAD a vibration hiway speeds.New front driveshaft fixed it.

 

If you can put the rear end up in the air and with the truck running in gear take a look at the drive shaft and see if it is smooth . If the drive shaft is vibrating I would try taking the middle universal out and give it a 180 and see if that helps any . The service manual suggest putting two hose clamps on the shaft and moving the heaver screw end around the shaft until there is and improvement . It sure sounds like the drive line has a problem to me but it could be any were . My dealer was dumber then a rock so I had to fix myself when it had a very similar problem