After a good day of mountain biking with my daughter, I got into her 300E. Pulled the half shaft, opened it up and everything looked and felt fine.

Turns out it was the LR wheel bearing. With the car jacked up there was quite a bit of play. Any previous wheel bearing failures that I experienced seemed to have a relatively consistent noise. This only was noticeable under load, hence the thought that it was a CV joint.

Oh well, time to fix a good dinner. Pull the carrier, etc., order parts and fix another day.

BTW, glad you found the tools at Autozone, JimSmith!!