Marcelo Boni assembled a series of images that separate rear PTO gearboxes into eight types. 1) I didn’t know there were that many and 2) I never thought to do this. Unfortunately, this is currently on Facebook, so not everyone will likely see it.
https://www.facebook.com/groups/18657808157/permalink/10160989656268158/
He wrote, “After a post on the CJ2A forum a long time ago
“Dating a rear PTO gearbox”
I started gathering pictures of Rear PTO gearboxes. I was expecting to identify the box period correct for my 1952 CJ3A.
I found 8 different variations.
Early ones are 24/20 tooth configuration.
When does the tooth config have changed to 22/22?”
If anyone knows the answer to that questions, I’ll make sure he gets the info.
Willys Overland Service Bulletin No 49-7, dated March 14, 1949, states “The power take-off gear ratio in the rear unit was changed from 20-24 tooth gears to 22-22 ratio, beginning with Model CJ-3A Vehicle Serial No. 13639.”
Thanks Bob! I let Marcelo know.
Bob, Marcelo was grateful for the info!