I am also running a 1660, cummins, inclined auger, etc.
Developed a slow oil leak last season on final drive under cab. Enough of a leak that it ran down inside of tire if sitting in one spot for a month or so.
Pulled tire and final this season before harvest. Outer bearing/race were shot.
Bearing and race was $235.
The other final is not leaking but is getting pulled this winter for a look-see.