HARD SHIFTING IN 1ST/2ND & REV (INSTALL MODIFICATION KIT)

SUBJECT: HARD SHIFTING (INSTALL MODIFICATION KIT)

VEHICLES AFFECTED: 1988 - 1991 W7 WITH FULLER 6-SPEED (FS6106 TRANSMISSION (RPO MZT)

Some owners of 1988 - 1990 W7 vehicles may experience hard shifting in first, second, and reverse gears. To correct this condition, a modification kit has been developed which increases the mechanical shift ratio. This may eliminate the hard shift condition. The Service Procedure below explains the installation procedure.

SERVICE PROCEDURE:

Shift Lever Extension and Replacement of External Select Lever

1. Block Rear Wheels.

2. Disconnect shift knob from shift lever Refer to Figure 1.

3. Connect new extension to shift lever, torque to 45 N.m. (33 ft. lbs. ).

4. Connect shift knob onto shift lever extension.

5. Tilt cab forward.

6. Disconnect negative (-) battery cable from battery.

7. Disconnect shift cables from shift levers Refer to Figure 2.

8. Disconnect upper shift cover (quadrant box) from lower cover.

9. Disconnect Link Rod.

10. Disconnect external selector lever by removing key (wedge) bolt and nut Refer to Figure 3.

11. Disconnect washer and oil seal from internal select lever.

12. Disconnect spring pin from shift shaft.

13. Disconnect internal shift lever.

14. Disconnect shift pivot bracket bolts and remove pivot.

15. Discard shift lever/shaft.

16. Connect shift pivot bracket bolts, washer, and nut to new shift lever/shaft.

17. Connect spring pin.

18. Connect internal select lever, oil seal, and washer.

19. Connect new external select lever using existing bolt, nut, and washer.

20. Connect link rod and change length from 173 mm to 181 mm (6 11/16 in. to 7 1/8 in.) Refer to Figure 4.

21. Connect upper shift cover (quadrant box) to lower cover.

NOTE: The left rear and right front bolts have a thicker neck that serves as dowels for cover alignment.

Clutch Mini Pack Refer to Figure 5

1. Replace bracket, spring bracket, spring, spring washer and nut.

Cable Adjustments (Figure 6)

1. Adjust select cable to 368 mm (14 1/2 in.).

2. Adjust shift cable to 324 mm (12 3/4 in.).

NOTE: After all adjustments are completed, torque relay link nut and jam nut to 26 N.m. (20 ft. lbs ).

3. Connect negative (-) battery cable back to battery.

4. Lower Cab.

5. Remove blocks from rear wheels.

6. Test drive vehicle to determine correct transmission operations. All six forward gears and reverse should be operable.

SERVICE PARTS INFORMATION

The kit part number is #94060388. The kit consists of the following components:

Part Number Description Qty. ----------- ----------- ----

94060386 Extension Lever 94060384 External Selection Lever 1 94060385 Shift Lever 1 94060383 Spring Bracket 1

WARRANTY INFORMATION

For vehicles repaired under warranty use:

Labour Operation: K2240

Labour Time: 1.5 hrs.

UPPER AND LOWER SHIFT COVER LEGEND (Figure 3)

92. 1st and Reverse Shift Arm 93. 2nd and 3rd Shift Arm 94. 1st and Reverse Spindle 95. Spindle Washer 96. Spindle Nut 97. Spindle Split Washer 98. 1st and Reverse Shift Block 99. Internal Shift Lever 100. External Select Lever 101. Select Lever Bolt 102. Select Lever Washer 103. Taper Bolt Washer 104. Select Lever Nut 105. Select Lever Split Washer 106. Shift Lever Shaft 107. Internal Select Lever 108. 1st and Reverse Shift Rod 109. Detent Spring 110. Detent Ball 111. Internal Lock Ball 112. Internal Lock Pin 113. 2nd and 3rd Shift Rod 114, 4th and 5th Shift Arm Rod 115. Transmission Quadrant Box 116. Quadrant Box Bolt 117. Harness Clip 118. Quadrant Box Washer 119. Gasket 120. Split Washer 121. Shift Lever Wire Pin 122. Shift Lever Split Washer 123. Nut 124. Upper Quadrant Box 125. Bolt 126. Cover 127. Oil Seal 128. Washer 129. Needle Bearing 130. Needle Bearing 131. Stopper Spring Pin 132. Cover Bolt 133. Split Washer 134. Washer 136. Gasket 137. 1st and Reverse Shift Block Sleeve 138. Cap 139. Shift Sleeve Lock Ball 140. Shift Sleeve Return Spring 141. Spring 142. Pin 143. Relay Lever Bracket Bolt 144. Bracket 145. Select Lever 146. Lever Bushing 147. Bushing 148. Nut 149. Split Washer 150. Relay Lever Bracket Nut 151. Relay Lever Bracket Washer 152. Relay Lever Link Rod 153. Screw 154. Nut 155. Washer 156. Nut 157. Neutral Switch 158. Backup Lamp Switch

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.