[rotorwrench]

The serial prefix doesn't match US or Canadian numbering system that I'm real familiar with. The 81-7222 casting number indicates it is 81A or production beginning in 1938 (double detent housing) and it's a good one. The serial number really doesn't matter all that much and you may have a transmission from a late 1947 or early 1948 pickup with an H model six cylinder engine but I haven't seen the VIN for those. As long as it has the 78 case then it's usable. If it is original to a pickup, it will have the open drive rear housing set up. These have a different main shaft than the ones made for closed drive but they can easily be converted either way. There were two types of synchronizer used in the 1939 thru 51 light duty 3-speed transmissions. One has the ball & spring plate detents and the other has the spring rings and flat plate detents but they are interchangeable.