Hey Old Koot:
35 years ago I started with AD trucks and I have a hand brake off one, but I don't know the year. There are threaded lugs on the side of the 4 speed trannys to accept the lever mechanism.
I suspect the older style ie 1946 had a hand brake. I don't think any of the 3 speed AD trannys that I have seen have the threaded lugs for the hand brake.
Good Question!
Ter
