I'll second the 'durability of IH final drive setups.
When I got my 66 int cub, it was mostly in good repair, and excelent 'looking' shape.
Minor details, like a pinched wiring harness to the lights, a few dirty electrical connections on the lights, switch, and the V-REG.. easilly fixed.. also, bad ammeter.
Fluids looked maintained well.. though, the oil bath in the fan hub was empty, and the only thing int he final drive pans was a light coating of dust... no evidence that ol ever was inthere. In fact, I'm glad i didn't drive it any till my service manual arived, and I started checking things like fan hub oil, etc.
I do know why the final drives were dry though.. you have to remove the drawbar, and belly mower to get at the plugs, etc.
All is filled now, and no leaks.
I did inspec the final drives a bit before re-assembling, and there wasn't even the slightest hint of wear.. so I was realllll happy.
Soundguy