I am getting a whine where i think might be coming from the transmission. It only happens in one instance though.

Only when i have the shift lever on the L.H. fender shifted into 3rd gear i get a whine in all other sub-gears, 1,2,3, and Reverse. This used to only occur when it was cold outside and until the tractor warmed up but now it happens all the time.

Has anyone else experienced this and if so what was it and what did you do to fix it?