rock331, The same case "590474" is listed as used in all 4 speed applications for 1931-47 trucks (except LT) as noted in the screenshot below. Same case but different other parts depending on the year built. A check of the
GM Heritage site files shows the "QM" serial number designation used on 1947 3100 and 3600 trucks as the RPO 4 speed transmission (built in Toledo).
If you want to confirm the other two transmissions you have, post those serial numbers so we can try and help confirm what they are.
