96 F150 - just bought it. When you get to 50 mph it starts vibrating terribly and loud "road noise". Thought it was tires - replaced those today and balanced --- no fix. ANy thoughts? Someon said it may be a u-joint? If so, I would I diagnose that? Thanks in advance.


Jon

 

Engine running, foot on brake, shift between D and R, listen for a clunk, if yes that could be slop in the univ joint.
Grab the drive shaft and give it a firm shake to confirm.

Cheap simple job to change with hand tools, watch videos on youtube.
Mine was so bad (E350 van) there were no roller bearings left in the yoke.!
Jack stand both rear wheels off the ground, in neutral, so you can rotate the drive shaft to get at all bolts at the univ joint.