Vibration @ 40 MPH
 

Hello everyone, I've been lurking on the forum since getting my 2005 Quad Cab in March. V6 auto 2wd with 88K miles has in the last couple weeks developed a vibration between 38-42 mph.
So this weekend I checked the driveshaft and the carrier bearing rubber is a little worn out. Can move it about a 1/4" with quite a bit of pressure. It didn't seem to be what's causing the vibration, so I put the rearend up on jackstands, pulled the tire off and ran it up speed just to be sure in not a tire issue.
Tried it in 2nd, drive and overdrive and vibration is still at the same speed. Started poking around and the transmission housing and front section of the driveshaft are hot to the touch. I did just get home after a 30 mile round trip of mostly hwy driving so I expected the transmission to be warm, but the driveshaft being hot was quite a shock. How much play should there be in the carrier bearing? Do I have a bearing going bad on the transmission tail shaft? I'm open to suggestions.
Thanks

Known problem. Not necessarily a known solution. I, for one, have experienced a decrease in the harshness of the vibration with a slight decrease in tire pressure (leading me to believe it was a harmonic problem with my steel wheels). But other people had the same wheels and reported no problem, while others had different wheels and did have the problem.

Interesting that you still had the vibration with the wheels off, same speed in different gears. It's gotta be post-transmission somewhere.

I think we're all waiting to figure out a solution. But other than a vibration, it doesn't seem to have affected anyone's trucks with any harm, even those above 100k miles.