my son bought a 86 fj60 last month. it has a vibration starting at 50 mph and gets worse as speed increases. you can feel it in seats and floor. transfer shifter has vibration in it but not transmission shifter. it makes dash vibrate and rattle. i tightend rear pinon nut about half a turn. jack up rear and brought speed up. at about 45 you could see vibration in front part of driveshaft. rear of shaft looked to be stable with no vibration. i suspected bent or out of balance shaft. bad u-joint or worn splines in slip joint. took drivelines to driveline shop. they said u-joints were al good. shaft was fine and in balance. he said front shaft splines had a little wear but not enough to replace. did not charge anything as needed nothing. then checked front and rear output flanges on transfer case. they have no loosness or wobble. wheel bearings are good. tires were almost new BFG 31x10.50. bought new BFG 31x10.50 and balanced. installed 4 new monroe magnum shocks.still have same vibration. we changed fluids in transmission and transfercase. cleaned old grease from u-joints and shaft then re-greased all joints. still has same vibs. do you think transfer case bearing are bad even though they feel ok? what about bad gear or gearshaftin transfercase? HELP!
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