Looks like the previous owner of our quad was riding with a broken hose barb on the rear gear case (right barb). He had the broken shaft shoved in the case hole, but you can see that it has had dirt/mud in it.

I really don't want to buy a new case, and it does not look like the barb is able to be purchased. Everything works and sounds fine, and I am going to change the gear oil several times to flush it clean.

I am thinking about taping the case hole and threading in a new brass hose barb. It looks like the case wall is plenty thick.

Has anyone had this problem or have any suggestions? What is the best gear oil to use?

Thanks for the help.