Originally Posted by supershaft
Don't make the mistake of thinking that the changed helical gear pressure face angle is the angle of the helical. That is the same for both PFA's. The difference is in the shape of each individual tooth and it is hard to see just by looking.
IIRC, there is an identifying mark on the output shaft helical gear.
Is there one on the input shaft gear as well ?
How about the layshaft ?