93 4r vibration when accelerating..help

i have a 93 yota 4 runner automatic 3.0v6 4wd, when i reach 40 or more mph i get a vibration along with a kind of roar or growl, as soon as i let off the gas it goes away, but will return if i push on the gas again, seems to be worse at higher speeds 65-85mph. checked fluids and seem to be fine

This vibration in these years is probably the transfer case output shaft yoke nut, big hurkin thing! You need to take the U joint off to tighten.
DO IT SOON! The vibration is pounding out the bearing and wearing the splines of the output shaft.
Easy cheap fix!
Good Luck (repost and let us know)

http://www.automotiveforums.com/vbulletin/showthread.php?t=444794

checked it, fine, any other ideas?

It does sound like the drive train has a worn component,(lose). U-joint would be the next thing, wheel bearings.
A mechanics stethoscope is great to use here, with the vehicle on the hoist let it idle in gear and "listen" to each bearing location through out.