Originally Posted by jporietis
The only way to fully check U joints is to remove the drive shaft. Leaving the shaft in will not readily show a problem.
You are absolutely correct. To fully check the driveshaft I would have pulled it and inspected tip to tale. My inspection was a simple look at all 4 caps on each u-joint looking for any sign of slop. Each leg of the u-joint appeared to fit snugly and symmetrically in their respective caps. There was no sign of grease being slung. To be sure that I didn't possibly have a dry u-joint I gave them a turn with the grease gun and didn't get more than 3-4 squeezes before they were full.
I don't believe it is/was a u-joint wear/damage issue.
I am leaning toward the probability that my "Travel" mode did not engage properly when I left the campground. Why? Because on the trip to the campground I had none of the vibration. The vibration began almost immediately after I departed the campground headed home. I did two things when I stopped and one of those two immediately "fixed" the issue. One was adding 500lbs of fuel up front and the other was a reset of the leveling system. One of those two cured the vibration 100%. Being new to this RV I wrongfully assumed that it had leveled properly when I got the "Travel" light. Maybe it did and maybe it didn't....evidence is gone now. If indeed that is what happened I will insure that it does not happen again. Future walk around inspections will include a close look at ride height.