Chevrolet 70 1969 Series, Shop Manual

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TRANSMISSION AND CLUTCH 7-8
TRANSMISSION CONTROL COVER DISASSEMBLY
1. Using tap handle and EZ-out, or equivalent, as
shown in Figure 9, remove lock pins (14) which se­
cure shift forks and shift lugs to shift rails.
2. With all shift rails positioned in “ N eutral,” remove
one shaft rail at a time, driving expansion plugs (19)
out of cover (21) as shift rails are driven out. Shift
forks and shift lugs are stripped off as shift rails (34,
35, 36, and 24) are driven out of cover (21).
NOTE: Care should be taken not to lose inter­
lock pins (28), interlock balls (27), poppet balls
(25), and springs (26) as shift rails are re­
moved.
3. 1st (17) and reverse (98) shift lugs are identical and
a. Remove retaining washer (18).
b. Remove plunger spring (29) and shift lug plunger
(30) from each shift lug (17 and 98).
MAIN DRIVE GEAR DISASSEMBLY
1. Using a spanner wrench, remove drive gear bearing
retaining nut (59). N ut is staked into slot of shaft
(57).
2. Using bearing remover plates (J-8176), press drive
gear bearing assembly (58) off drive gear shaft (57).
3. Using snap ring pliers, remove snap ring (55). Re­
move retainer washer (54) and 14 needle bearing roll­
ers (56) from cavity at rear end of main drive gear
(57).
MAINSHAFT DISASSEMBLY
1. Remove 1st speed sliding gear (41) from splines at
rear end of mainshaft (31).
2. Depress 2nd speed gear lock pin (33); then turn 2nd
speed gear locating thrust washer (41) until internal
teeth of thrust washer align with splines of mainshaft
(31).
3. Hold lock pin (33) which is spring-loaded and remove
thrust washer (40). Remove lock pin (33) and spring
(32).
4. Slide 2nd speed gear (39) off rear end of mainshaft
(31).
5. Remove 2nd speed inner stop ring and pin assembly
(49), sliding clutch (50), 3rd speed inner stop ring and
pin assembly (51), and 3rd speed outer stop ring (13)
from mainshaft (31).
6. M ount mainshaft assembly in a vise with soft jaws.
Remove synchronizer front inner ring and pin assem­
bly (5), 4th and 5th speed sliding clutch (6), rear inner
ring and pin assembly (7), rear outer stop ring (8),
and shims (9) from front of mainshaft (31).
NOTE: Record number of shims (9) removed,
Same number of shims should be installed
when transmission is reassembled.
7. Using snap ring pliers, remove snap ring (2) from
groove in mainshaft (31). Remove clutch gear (3) and
4th speed gear (10) from mainshaft (31).
8. Remove both halves of split retaining ring (11); then
remove 3rd speed gear (12) from mainshaft (31).
COUNTERSHAFT DISASSEMBLY
1. M ount countershaft assembly (71) in an arbor press.
2. Using bearing remover plates (J-8176), press counter­
shaft drive gear (68), 4th speed gear (69), and 3rd
speed gear (70) off countershaft (71). Remove gear
key (72) from slot in shaft (71).
NOTE: 1st speed gear teeth, 2nd speed gear
teeth, and reverse gear teeth (28, 29, and 30,
fig- i) are integral with countershaft (71).
CLEANING, INSPECTION, AND REPAIR
(Refer to Figure 3)
CLEANING
During overhaul procedures all components of the
transmission (except bearing assemblies) should be thor­
oughly cleaned with cleaning solvent and dried with air
pressure prior to inspection and reassembly of the trans­
mission.
1. Clean the bearing assemblies as follows:
a. Careful and proper cleaning of bearings if of ut­
most importance. Bearings should always be
cleaned separately from other parts.
b. Soak all bearing assemblies in C L E A N cleaning
solvent. Gasoline is not recommended. Bearings
should never be cleaned in a hot solution tank.
c. Slush bearings in solvent until all old lubricant
is loosened. Hold bearing races so bearings will
not rotate; then brush bearings with a soft bristled
brush until A LL D IR T has been removed. Re­
move loose particles of dirt by striking bearing
flat against a block of wood.
d. Rinse bearings in clean solvent; then blow bear­
ings dry with air pressure. DO N O T S P IN
B E A R IN G S W H IL E D R Y IN G .
e. Rotate each bearing slowly while examining balls
or rollers for roughness, damage, or excessive
wear. Replace all bearings that are not in first
class condition.
NOTE: After cleaning and inspecting bearings
as directed, lubricate bearings generously with
lubricant recommended in LUBRICATION (SEC.
10) of this manual; then w rap each bearing in
clean paper until ready to reinstall in transmis­
sion.
2. Remove all portions of old gaskets from parts, using
a stiff brush or scraper.
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L