The folks that I worked with on the PTO rebuild is Inland Truck in Missoula Montana. I found them by googling and calling U.S.-wide anyone who indicated they did work on older PTOs, even some here in Boise who bailed as soon as I indicated my truck is a '48. Most of the trucking companies are in the repair or remove and replace business with current models and mostly electric or electronic PTOs on big stuff. They were nice about it, mostly just gave me the "go away please" treatment. Then I found the guys in Missoula. They are part of a very large trucking service and parts company. The closest branches to me were in Denver and Missoula, so, Missoula being closer, I called them. Randy answered the phone. He is the service manager and he was most helpful and told me he had 30 years experience and Ken (the General Manager) had 40 so they should be able to help. He was totally familiar with GarWood and told me to send it up. After that, Ken took a personal interest himself and even sent my worn shifter out to a friend for some some needed machine work before reassembly. Anyway, here's their info if you can use it. I hope it can help you as they helped me.
https://www.inlandtruck.com/locatio...ign=gmb&utm_content=montana_missoulaBTW Tom, I have looked high and low for any manuals for these old GarWood PTOs and never found anything, so congrats on the Arrow find. Guess the new puppy was looking too?