I still haven't has time to work on it.  I am reviewing the service manual.  Do I really need to remove the rear gear case to tighten the pinon?  Seems like a lot of unnecessary work.

The driveshaft does have some forward and backward movement... back toward the read end under load and toward the engine maybe 1/4inch when coasting.  It has a slight clicking noise in the input shaft area of the rear differential with a stethoscope when coasting but no noise under load. Thats the only place I can hear or see anything.   I will check and advise.  It appears I can replace the bearing without major surgery. I will check and advise.   Thank you.

I can't find that specific term in the service manual.  Is #9 in the attached pic what you are referring to?

So maybe nothing broken?  It's out of warranty 7 month.  The 12 month expired last June 23.   I have the service manual and am fairly mechanically adept.  Guess it will pull it apart.   Thank for the reply.

I have a 2022 U Force 600 we bought new in June of 2022.  It is just under 200 hours.  Serviced regularly.  Most of our driving is under 19 mph so we drive it in Low as per the owners manual.  Recently we started getting what I would call a loud gear whine on deceleration.  It sounds like it's coming from the rear differential.  Anyone have ideas on what it could be or how to proceed?