1986 89 TRANSMISSION IDENTIFICATION DURING THE 1985 MODEL YEAR AND THE START OF 1987 PRODUCTION THE FOLLOWING TRANSMISSIONS WILL HAVE A THREE 3 LETTER CODE AS OPPOSED TO A TWO 2 LETTER CODE PREVIOUSLY USED THE THIRD LETTER IN EACH CODE WILL IDENTIFY TRANSMISSION TYPE 3RD LETTER TRANS TYPE OPTION A 400 M40 B 2OOC MV9 C 125C MD9 F 200 4R MW9 H 440 T4 ME9 M 700 R4 MD8 Z F 7 ME9 j 2 1989 GENERAL MOTORS SERVICE PARTS OPERAT ONS BUICK 44J REV 10 89 4 47 4 499