Ford: vibration in drive train, rear drive shaft, wheel bearing

Question
Vibration in drive train 2003 ranger 3.0 2wd automatic trblshooting method raised rear end off ground, ran in drive with no load had vibration, removed rear wheels, had vibration, removed brake drums, ran had vibration, in reverse the vibration is gone, backwards trblshooting method no vibration up to wheels back on truck off the ground. Noticed inspection rear drive shaft u joint has a grease fitting took around 6 pumps to fill the joint, forward does not could this be a 1 or both ujoint issue ? noticed load clunk noise when going from reverse to drive periodicaly and startring to notice clunk or thump when slightly ramping up on accelerator now also. Transmission is shifting fine no whining sounds at all smooth shifting through all gears Vibration is very predominant at 40mph to 60 particularly on accelerration at allmost any speed, have started to notice vibration at declining speed to stop. Or wheel bearing issues / ujoints/ or possible transsmision issue? Please advise.....

Answer
Hi,

With vehicle in neutral and wheels blocked, look for any play in u-joints, support bearing(if applicable) and in pinion (yoke at diff)

Some up and down and side to side movement in center (support) bearing is acceptable, as it rides in a rubber ring. some cracks in the rubber are common as well.

There should be no movement in the u-joints, and look for rust at the cups= bad.

you should have a small amount of turning at the pinion (backlash)maybe 1/8 turn max but no in and out or up/down or side to side movement= bad pinion bearing or loose yoke.