How to Identify a Saginaw Transmission?
Saginaw transmissions can be identified by the material of the case, the position of the shifter arms and transmission codes. Produced in three- or four-speed models, these manual transmissions were installed in a number of GM cars, including the 1967 Chevrolet Camaro and 1969 Chevrolet Impala.
Unlike Muncie transmissions, another staple of GM cars during the era, Saginaw models feature a cast iron case instead of an aluminum one. Saginaws also had shifter arms fitted on the side cover of the case, not on the tailshaft.
Transmission identification codes can provide positive identification of a transmission. Saginaw models should have the code stamped on the plate located next to the rear cover, on the lower right side of the case. For example, the codes used for Chevrolet cars began with "R" for Saginaw four-speed types and "S" for three-speed models. A series of numbers and characters follow the code letter, indicating date and time of assembly.