Et tu rear axle?

[Bowesmobile]

I have a working transmission! Yay! Now I have a rumble and vibration from 45 - 75 mph or more and it sounds like the rear axle is giving up on me. This started three days before the trans went and I thought it was caused by the extension housing bolts backing out of the original trans. I had hoped it would have been solved with the replacement trans and transfer case. Now I plan to check the rear axle. I checked the driveshaft, tailshaft on the transfer case and flange on the rear diff when installing the driveline with no real play. But its feeling like theres more rumble from the passengers side wheel. I guess Ill start there. I just wanted some initial input from my expedition brothers and sisters.

 

[Bowesmobile]

I changed the u-joints and the vibration is the same. Im thinking the rear axle is shot or i have a rear tire way out of balance...I've wondered if the transfer case is stuck in 4wd. Something I need to research more.