i have a 3rd gen sas toyota 6 in lift, 4.88 gears, 37" toyo mt, and i finally got the truck running again. it has sat for a little under two years and got enough money to get it going. my problem is when i take off in 1st it has a bad vibration from the rear, then go to 2nd and goes away, but once it reaches 55 there's sort of a pulsation coming from the rear...could it be the u joints in the drive line went bad? i checked the pinion and there's no play front to back so its not loose and the gears seem to engage fine...and how much play turning the pinion should there be?

 

first off, check the u-joints for play... if so, then thats where your problem is, and im willing to bet thats the problem... mine does the same thing...

as for the rear end, if it WERE going out, then most likely it would be producing a whining/grinding sound (zuk calls it "singing") coming from the rear but there wont be any "vibrations" so to speak...

 

turns out it was the ring gear was f'd up because the pinion was set to close to the carrier...anyone know how to adjust that?

 

uhhhhh take apart and put shims behind it kinda a pain in the A$$

 

uhh if its to close he would want to take some out

read abunch here, http://www.gearinstalls.com/