Hey fellas, recently after some wheelin' off road with some buddies I noticed a distinct vibration on the highway. If I'm going 70 and put my hand on the shifter, it has a high-frequency vibration. If I push the clutch in, it gets a bit worse.

Also I was hooning around tonight and got the rear end out a little around a corner and now the vibration can be felt through the floor/steering wheel dependent on RPM and speed.. like there are two separate vibrations now. It also sort of resonates in the cab with engine RPM.

The U-joints seem tight but I've read a lot of cases where they are, but people will remove them and they're absolutely toast. I'm thinking engine/trans mounts. Any ideas? Thanks, Nick

 

Sounds like you gotta a dried out u joint cap, rollers in one or more caps are still there but rusty/crusty causing the vibration you feel.

 

Check the driveshaft(s) for mud/debris stuck to them or thrown weights. U-joints are also a possibility along with a carrier bearing (if your truck has one)