VCCA Home Forums TECHNICAL - 1945 AND NEWER 1949-1954 How to identify early PowerGlide transmissions

Can anyone tell me where I can find information on how to identify early PowerGlide transmissions? Is there a casting number reference that would help me figure out what I'm looking at? I understand that the earliest models did not shift automatically from low to high. When did that become a standard feature? Could I tell by casting numbers or any other other external features whether or not the tranny is an "autoshifter"?
Thanks for any help.

I know the early ones were cast iron and not aluminum.

The early PowerGlides were cast iron and didn't have a removable sump pan. I think the aluminun cased units arrived in 1962 or thereabouts.

The "auto-shifter", as you stated, arrived in 1953. The '53 and later had a governor housing that the first three years didn't have. The governor housing is a half round sphere cap located on the left side, rear edge of the main housing (maybe the size of a tennis ball). There is a bell crank unit located at the case left front lower edge used for the throttle linkage which controlled the forced downshifts.

That's about all I remember about them except they were heavy and difficult to disassemble and reassemble without the proper equipment.

The main case had casting number 3692962 for 1950 and 1951.
The 1952 had 3693235 on the case.
The difference between the two is the location of the transmission mount holes in the case.
The 1953 and 1954 had 3702601 or 3703283 on the case. The 3702601 was used in 1953 but the two interchange.
The 1955 and up are designed to be used with an open drive shaft.