I have rebuilt several of these trannys... i never buy zf bearings or seals
because a thirnd party makes them ...why pay 4 times as much... for the bearings i write down the bearing number and call my local NAPA auto parts
store the seals
i measure look up the part number from a pdf file and call napa with the number... they are simple trannies and usually fail due to lack of use... the input shaft bearing is highest in the case and rusts first... rust then wears out.. when winterizing your boat the tranny should be COMPLETELY filled to the top ....then drained in the spring and topped to the correct level ..
the only bearings that may be difficult to find are the 2 small carrier bearings that the 2 gears ride on... and i have seen one of these fail also