I I GM05 O I71 RPO DEFINITIONS JA1 BRAKE SYSTEM LIGHT WEIGHT D SC DRUM I JA2 BRAKE SYSTEM HEAVY WEIGHT DISC DRUM MD8 TRANSMISSION AUTOMATIC 4 SPEED THM7OOR4 4L60 Y01 7 50 DIAMETER RING GEAR SAGINAW REAR AXLE YO4 8 50 DIAMETER RING GEAR SAGINAW REAR AXLE 9C I POLICE CAR 9C6 TAXI CAB I 1 1992 GENERAL MOTORS SERVICE PARTS OPERATIONS CHEVROLET 178 5 000 GROUP 5 14 8 92