Originally, there would be a stamped label. It would be either on the opposite side of the case or just above the rear of the pan rail and to the driver's side of center. It'll have the tranny serial number, starting with year and a one or two letter type that will identify what vehicle it left the factory in.
Pages below are from "The Hydra-Matic Transmission 1946-1955 On The Car Adjustment Service Manual. They don't cover later models. Olds and Pontiac used these dual-range Hydra-Matics through 1956, Chevy trucks through at least 1959 and GMC until at least 1962,
Last edited by Bill Hanlon; 04/24/202212:08 AM.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
