GMC 1989 Light Duty Truck, Repair Manual, Page: 926 / 998

7B4-2 BORG WARNER TRANSMISSIONS
DISASSEMBLY OF THE 77 mm TRANSMISSION
600. Screw
626. Pin Roller
601. Shift Cover
627. Lock Spring
602. Seal
628. Reverse Shift Fork
603. Transmission Case 629. 5th Speed and Reverse Shift Shaft
604. Mainshaft
630. 5th Speed Synchronizer
605. Bearing Race 631. 5th Speed Blocker Ring
606. 5th Speed Gear Snap Ring 632. 5th Speed Drive Gear
607. Retaining Clip
633. Snap Ring
608. Ball 634. Countergear Spacer, Rear
609. Speedometer Drive Gear
635. Countergear Ring Bearing
610. Snap Ring
636. Countergear Spacer, Front
611. Front Thrust Race
637. Reverse Idler Shaft
612. Countergear Thrust Bearing
638. Reverse Idler Gear
613. Extension Housing
639. Pin
614. Screw
640. Countergear
615. Funnel
641. Countergear Thrust Washer
616. Snap Ring 642. Countergear Front Bearing
618. 5th Speed Shift Fork
643. Main Drive Gear
619. Pin
644. Main Drive Gear Bearing Race
620. Pin Roller
645. Bearing Shim Pack
621. Shaft Pin
646. Main Drive Gear Bearing Retainer
622. Fork Pin
647. Screw
623. 5th Speed and Reverse Shift Lever
648. Magnet
624. Pivot Bolt
649. Nut
625. Retaining Ring
B-Q8501
Figure 1— 77 mm Transmission and Components
Rem ove or D isconnect (Figures 1, 2 and 3)
• Speedometer driven gear, switches and any external
components.
1
. Control lever (653).
• Boot and the dust cover.
2. Pin (659) from the offset lever (655), (figure 4).
3. Extension housing (613) and the offset lever.
Im portant
• The offset lever is engaged into the extension
housing and cannot be removed when the ex­
tension housing is mounted to the transmis­
sion.
4. Detent ball and the spring from the offset lever, (fig­
ure 5).
5. Countergear rear thrust bearing (612).
• Plastic funnel (figure
6
).
• Front thrust race.
6
. Shift cover (601).
Im portant
• Two of the cover mountir
ment screws. Note the po
moved from for installation.
7. 5th speed drive gear (632).
• Support the 5th speed shift fork (618) and
drive the pin out, (figure 7).
8
.
9.
10
.
11
.
12
.
13.
14.
15.
16.
^screws are align-
tions they were re-
17.
18.
• Snap ring and the 5th gear synchronizer (630)
and shift fork together (figure
8
).
• 5th speed blocker ring (631) and the 5th speed
gear (632).
Speedometer drive gear (609) and the clip.
5th speed driven gear snap ring (606).
Main drive gear bearing retainer (646).
• Mark the retainer and the case for alignment
(figure 9).
Bearing race (644) and the shim pack (figure 10).
Main drive gear (643).
• Turn the gear so the cut-out is toward the
countergear (figure
11
).
Retaining ring and the reverse shift shaft lever pivot
bolt (624) (figure 12).
Mainshaft rear bearing race (605).
Mainshaft (604).
5th speed and reverse shift shaft (629) (figure 13).
• Unhook the lock spring.
• Turn the shaft to disengage it from the reverse
lever.
• Remove the shaft from the rear of the trans­
mission case.
5th speed and reverse shift lever (623).
Reverse idler gear (638).
• Drive the pin through the front of the idler
shaft (637) (figure 14).
• Idler shaft and the seal.