The Muncie or Saginaw three speed manual transmission serial number is on the left side of the case next to the rear of the cover. The three speed top-cover Tremec transmission (1976 and later) has the number on the upper forward mounting flange. The four speed transmission is numbered on the rear of the case, near the output shaft. The Turbo Hydra-Matic unit number is on the right rear surface of the fluid pan. The unit number on 700R4 transmissions is stamped on the right side of the transmission. See for transmission and transfer case identification.