Does anyone know what the difference between a K51A and a K51B TUFF TORQ hydrostatic transmission is on the JOHN DEERE LT 155? I recently put in a new pump and pump motor in the transmission but there is one part I am not sure if I installed it correct, the motor housing which I have a red x on it in the posted photos. I am not sure if I need to have it the way now or turn it upside down with narrow end facing up. The schematics they show are not helpful on the tuff torq site. An actual photo is much better to see clearly. The last photo is when I first opened the transmission up. I took a photo to know how everything is put together. But as you can see the pump motor housing is facing different than what they have in the schematics. Do you think something was put together wrong at the factory?