I I 1 1989 SPEEDO GEAR USAGE CHART 1 I 1 l TRUCK EFFECTIVE 1989 MECHANICAL SPEEDO GEAR S ARE NOT REQUIRED FOR ELECTRICAL VEHICLE SPEED SENSOR BUFFER REFER TO GROUP 3 682 V A 1991 GENERAL MOTORS SERVICE PART9 0PERATIONS LTTRUCKP52M 4 450 4 60 1 91