I have an 86 3/4 ton 4x4 that vibrates when you reach 55 mph. I have replaced the u joints (there are just 2 on the rear shaft) which did quiet it down some.... but the vibration/drone remain. I have noticed that when I push up on the drive shaft near the xfer case the mount below the xfer case allows the two to raise close to an inch. So I am curious to know if anyone can advise me to approx how much play there s/b in the xfer case mount as well as the xfer case bushing. I believe it is the "208 C". Seems the rubber mount would get harder over time and be less forgiving.
Thanks,
MS