Andy - Very interesting info on your "4-speed" set up. If you still have that, I'd love to see some pictures of the transmission overall and output end where this unit slides inside. On the '47 model year trucks, if GMC did the same as Chevy, there is an early '47 that looks the same as the Art Deco '46 and a later '47 that begins the new AD body style.
Interestingly enough, my brain must have been still a little foggy this morning. When I looked at the book again, I found in the very back the back cover actually has an inset pouch. In that pouch I found Change Notices 1 through 5 with a date stamps of NOV 1 1945, FEB 1 1946, APR 1 1946, JUN 1 1946 and JUL 1 1946. Each with from 2 to 5 pages of changes to part numbers listed by Page, Group and Item as well as other data like truck serial #s the part applies to.
All this leads me to want to dive a bit further into the recently acquired GMC books to see what I might dig up. I'll let you know what I find.
