on WD 45's is there a common cause for a bad gear whine or possibly a bad bearing in the rear end. New to me tractor I did not notice the noise when I bought it but when working on it I drained the trans/rearend oil and it had a fair amount of water in it I had the top of the tranny off to fix the shifter and put fresh 90wt back in it and now it has a loud whine or noise that you can hear in all gears although the higher the gear and faster you go it gets worse possibly a bearing running dry? Could I see anything if I took the back cover off the rearend or will I have to completly disassemble it. Any thoughts? Thanks