So I need two 10-18 standard rotation transmissions for TRS drives. The prop in one drive gets reversed in the drive so both engines & transmissions are standard rotation on my twin engine boat.

ok so I found one that says counter rotation. Can the pump be turned 180 degrees & things turn the other way? My guess is no.

the rubber donut that goes on the end where do I get one of those?

i need one more 10-18 trans & I now have 2 newly rebuilt 10-17s I don’t need what are they worth?
Cliff in maine