1 TRANSMISSION IDENTIFICATION TRANSMISSION TO ASSEMBLY CODES Note Transmission identification can be located in one of three positions cn the transmission A Identificatidn plate cn side of case B Stamping hummer on governor cover C Ink stamped OH bell housing 1985 MD9 3 SPD A T THM125C BP 2 84 RATIO PN 2 84 RATIO FRONT AXLE IDENTIFICATION 2 84 RATIO F17 OPTION BP PN 1986 MD9 3 SPD A T IRM125C MT2 5 SPD MAN GBA 3 18 RATIO ZF GBP 2 84 RATIO 6PN 2 84 RATIO 1987 MD9 3 SPD A T IRM125C MT2 5 SPD MAN 7NPC 2 84 RATIO 5zF 3 35 RATIO 7RDC 2 84 RATIO 7BJC 2 53 RATIO 1988 MD9 3 SPO A T THM125C 8KDC 2 84 RATIO BPNC 2 84 RATIO 8BHH 2 53 RATIO BBJH 2 53 RATIO 1989 MD9 3 SPD A T THM12 5C I 9BUC 2 39 RATIO 9PNC 2 84 RATIO 9KDC 2 84 RATIO 9KMC 2 84 RATIO 1991 GENERAL MOTORS SERVICE PARTS 0PERATIONS BU CK 44N 2 91 44 1 4 000