I have a 2007 Tahoe that has a vibration in the seat at 40 mph and up. I have been to the dealer several times with no help and no solution. I want to know if anyone has the same problem and maybe has a fix. The drive shaft and rearend has been replaced still have the vibration any help would be greatfull.

 

If the RPMs are around 1200-1600, there is a TSB on the torque converter. Do a search on it and you'll see all the info. I had the work done and the vibration is significantly dimished (not gone though).