WHOA...I didn't indicate that they were interchangeable. They may be but please don't assume that. There are tremendous differences in PTO's across the board and it isn't just whether they will bolt up and engage either. I once had a customer who broke the entire side out of a Fuller RR because his PTO had a higher torque rating than the transmission did so guess which one failed...? This is always a problem with twin countershaft transmissions but back to the Allison.
First of all a PTO for medium duty truck with a CH465 is likely but not necessarily to be a single gear unit. There are no single gear units that fit older Allisons. Next is the issue with lubrication that I originally pointed out. Single gears have no such provision. Next would be the torque issue. Lastly is the fact that even if it did fit it wouldn't protrude far enough away from the tranny to attach anything. All the AT PTO's are double gear. That means that the driven gear inside the PTO is always running and the output shaft gear engages off of it. A single gear PTO is a sliding gear that is engaged on the transmission only as needed.
Send me your model numbers and I'll track it down for you and tell you what you need, OK?
