I have a 93 250 diesel 5 speed with a two piece drive shaft. I am getting a vibration starting about 30 to 35 mph in 4th and 5th gear. It only happens under acceleration. It stops when I let off the gas or push in the clutch. My u-joints look good ( I can't see any excessive play). It is not coming from the front end and I have new tires on the back. Any help or direction would be appreciated.

Thanks,
Tom

 

Check the carrier bearing. I wouldn't rule out the U-joints yet either. And WELCOME by the way.

 

I have 250k on the truck and have never replaced the u-joints or support bearing. I can do it for about 100 bucks so I guess it is a good place to start.
Thanks for the info.

Tom