desertrat wrote:
I would recommend you pull the front driveshaft or bring it back to the dealer to ask them to do that, and then test drive your vehicle. If the vibration is not present with the driveshaft removed, you may have the same problem that I've had and that is the small boot going into the transfer case is ripped. At high speeds, it picks up a vibration because the grease has seeped out and the unit is heating up. By taking a flashlight, I could see the boot had disappeared on one side of the shaft and from reading other posts on this forum, this has happened with many other folks also.
I had the exact same symtoms that you have, with vibrations only at certain high speeds. Drove me crazy. Dealer had the car for days and couldn't identify. Finally took it to a drive shaft specialist that identified the problem. Identified immediately upon pulling the shaft. So if you've ruled out tire balancing and other options, then I'd do the next step of pulling the shaft and doing a test drive.
Thanks! I will pull it out on my next day off and see what happens. I'll keep you posted.