I saw a similar post but didnt help. I have a massive vibration problem on flat sufraces at 55mph but goes away at 60. doesnt matter if i hit brakes or let off throttle or putin neutral. vibration remains. It has a 5in susension lift and doesnt vibrate on dirt roads. I just bought it and am thoroughly baffled

 

bad front shocks and unevenly worn tires caused my truck to vibrate like a paint mixer over 50 mph.

new shocks and tires = feels like a new truck

could also be the u joints?

 

wheel balance was what caused my vibration at 55.

 

also check your trans case output flange. Those nuts back off causing a vibration with the rear driveline