T18 v TRUCK TRANSMISSION PRODUCTION CODE EXPLANATION The truck transmission codes are located as follows I I Three Speed Saginaw Type The code is stamped on the left side of the case just below the side cover The production code number contains the source code model year and build date E 2 A SOURCE CODE MODEL YEAR BUILD MONTH DAY CODE I S 3 Speed 1979 A Jan 10th Saginaw Type B Feb C Mar D Apr E May I H June I K July I M Aug I I P Sept 4 R Oct T S Nov T Dec l 2 Three Speed Tremec I The identification coda is located on upper left atnachment ear top side The production code number contains the source code month model year and build sequence EXAMPLE SU G H 0001 I SOURCE CODE MONTH YEAR BUILD SEQUENCE l Tremec A Jan 1979 B Feb C Mar D Apr E Mav F June G July H Aug J Sept K Oct L Nov I M Dec LLGEMERAL MOTORS SERVICE PARTS OPERATIONS LT TRUcK 52A i 39 l