GMC S Series 1994, Repair Manual

Page: 877 / 919

synchronizer sleeve is shifted into engagement with the
clutch hub teeth on the mainshaft. This locks the drive
sprocket to the mainshaft through the synchronizer
assembly. Torque is transm itted through the drive
sprocket by the connecting drive chain. Since the front
output shaft is splined to the driven sprocket, torque
flows through the front output shaft to the front propeller
shaft and axle resulting in high range four-wheel drive. In 4 L 0 range, the path of torque through the transfer
case is exactly the same as in 4Hi range but with one
major difference. In 4 L 0 range the range hub is shifted
into engagement with the planetary carrier. This causes
the input gear to rotate the planetary pinions inside the
fixed annulus gear, causing the planetary carrier, range
shift hub, and mainshaft to rotate at a qear reduction of
2.69:1.
DISASSEMBLY
EXTERNAL COM PONENTS
Clean
• The transfer case using a solvent and a stiff brush.
Remove or Disconnect (Figures 1 , 2 , 3 , and 4)
1. Front output flange nut (76), flat washer (56), rub­
ber sealing washer (57), and the front output flange
(58) from the front output shaft.
2. Rear output yoke nut (75), flat washer (56), rubber
sealing washer (57), and the rear output yoke (58)
from the main shaft.
3. Speed sensor (59) from the rear bearing retainer
(50).
4. Four-wheel drive indicator switch (60) from the
front case half (31).
5. Rear bearing retainer bolts (61) and rear bearing
retainer (50) from the rear case half (46).
INTERNAL COM PONENTS
«--► Remove or Disconnect (Figures 5 through 22)
Tools Required:
J 22912-01 Gear Puller
J 8433-4 Puller
J 8059 Snap Ring Pliers
J 8092 Driver Handle
J 29169 Bearing Remover/Installer
J 33832 Bearing Remover/Installer
J 2619-01 Slide Hammer
J 29369-1 Output Shaft Bearing Remover
1. Speedometer tone wheel (1) from the mainshaft
(23) using J 22912-01 and J 8433-4 or equivalent
(figure 5).
• Be careful not to install J 22912-01 under the
tone wheel snap ring.
2. Tone wheel snap ring (3) from the mainshaft (23).
3. Rear output bearing snap ring (4) from the main­
shaft (23) using J 8059 (figure 6).
4. Case screws (62) from the case halves. Note these
are self-tapping screws and aluminum shavings are
common upon removal.
5. Rear case half (46) from the front case half (31).
• Using a suitable tool pry between the two pry
bosses to separate the case halves.
6. Clutch coil wire connector (5) from the clutch coil
wire (figure 7).
7. Clutch coil nuts (6) from the clutch coil assembly
(7) (figure 7).
8. Clutch coil (7) from the rear case half (46).
9. Shift rail spring (8) from the shift rail (9).
10. Clutch coil housing snap ring (10) and the clutch
coil housing (11) from the mainshaft (2) using
J 8095 (figure 8).
11. S ynchronizer hub (55) from the synchronizer
assembly (12).
12. Synchronizer assembly (12) from the mainshaft
drive gear and mode shift fork (13) from the shift
rail (9) (figure 9).
13. Front output shaft snap ring (15) and flat washer
(17) from the front output shaft (16) (figure 10).
14. Drive gear (18), driven gear (19), and drive chain
(20) as an assembly (figure 11).
15. Front output shaft (16) from the front output bearing
( 22 ).
16. Mainshaft (23) and oil pump assembly (24) from
the input carrier assembly (25) (figure 12).
17. Shift rail (9), range fork (28), and shift hub (29)
from the input carrier assembly (25) (figure 13).
18. Annulus gear snap ring (30) from the front case
(31) (figure 14).
19. Annulus gear (32) from the front case (31)
(figure 15).
20. Input shaft oil seal (33) from the front case (31).
21. Carrier assembly snap ring (34) from the carrier
assembly input shaft (25) (figure 16).
22. Input carrier assembly (25) and power take off
drive gear (35) from the front case (31) (figure 17).
23. Retaining clip (36) from the sector shaft (37)
(figure 18).
24. Sector shaft (37) from the front case (31).
25. Sector (38), detent spring (39), and detent roller
(49) from the front case (31).
26. Front input bearing snap ring (43) from the front
case (31) (figure 19).
27. Front input bearing (44) from the front case (31)
using J 8092 and J 29169 (figure 20).
28. Rear output bearing (45) from the rear case half
(46) using J 8092 and J 33832.
29. Front output shaft rear bearing (85) from the rear
case (46) using J 2619-01 and J 29369-1
(figure 21).
30. Front output shaft seal (42) from the front case
(31).
31. Front output bearing snap ring (40) from the front
case (31) (figure 22).
32. Front output bearing (22) from the front case (31)
using J 8092 and J 33832 (figure 23).
33. Rear output shaft seal (47) from the rear bearing
retainer (50).