Chevrolet 70 1969 Series, Shop Manual

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TRANSMISSION AND CLUTCH 7-70
1. Using snap ring picks (J-8461-1), remove countershaft
drive gear retaining ring (32) from front end of coun­
tershaft (38).
2. Using suitable press or gear puller, remove counter­
shaft drive gear (33) (fig. 18), drive gear key (37), spa­
cer (34), countershaft 4th speed gear (35), and 3rd
speed gear (36) from countershaft (38).
3. Rem ove two rem aining countershaft gear keys (37)
from countershaft (38).
M A IN D R IV E G E A R A N D B E A R IN G
D IS A S S E M B L Y
N O T E : K e y n u m b e rs in text refer to Figure 21.
1. Position main drive gear (51) in a vise with brass or
copper jaw s so gear teeth will not be dam aged; then
using a large wrench, remove the bearing retainer nut
(49) (fig. 19).
2. Using bearing rem over plates (J-8176) and an arbor
press, remove m ain drive gear bearing (50) (fig. 20).
CLEANING, INSPECTION, A N D REPAIR
(Refer to Figures 2, 12, and 21)
C L E A N IN G
During overhaul procedures all com ponents of the trans­
mission (except bearing assemblies) should be thoroughly
cleaned with cleaning solvent and dried with air pressure
prior to inspection and reassem bly of the transm ission.
1. C lean the bearing assemblies as follows:
a. Careful and proper cleaning of bearings is of
utm ost im portance. Bearings should always be
cleaned separately from other parts.
b. S oak all bearing assemblies in C L E A N cleaning
solvent. Gasoline is not recom m ended. Bearings
should never be cleaned in a hot solution tank.
c. Slush bearings in solvent until all old lubricant
is loosened. H old bearing races so bearings will
not rotate; then brush bearings with a soft bris­
tled brush until A L L D IR T has been removed.
Rem ove loose particles of dirt by striking bear­
ing flat against a block of wood.
d. Rinse bearings in clean solvent; then blow b ear­
ings dry with air pressure. D O N O T S P IN
B E A R IN G S W H IL E D R Y IN G .
e. R otate each bearing slowly while exam ining balls
or rollers for roughness, dam age, or excessive
wear. Replace all bearings that are not in first
class condition.
N O T E : A fter c le a n in g a n d in sp e c tin g b e a rin g s
a s directed, lu bricate b e a r in g s g e n e ro u sly w ith
lu bricant re c o m m e n d e d in L U B R IC A T IO N (SE C .
0) of this m a n u a l; then w r a p e a ch b e a rin g in
clean p a p e r until re a d y to reinstall in tra n sm is­
sion.
2. Remove all portions of old gaskets from parts,
using a stiff brush or scraper.
IN S P E C T IO N
1. Inspect rods and shafts for evidence of fatigue.
Check bearing surfaces for scoring or wear.
2. Inspect all parts for discoloration or w arpage due to
heat.
3. Exam ine all gear teeth and splines for chipped, worn,
broken, or nicked teeth or splines. Sm all nicks or
burrs m ay be removed with a fine abrasive stone.
4. Inspect the breather assembly to see th at it is open
and not dam aged.
5. C heck all threaded parts for dam aged, stripped, or
crossed threads.
6. C heck all oil passages for obstructions, using brass
rods and air pressure.
7. Replace all gaskets, oil seals, lock wire, cotter pins
and snap rings. (If snap rings are not dam aged or dis­
torted and are not used for sealing as well as retain­
ing, they m ay be reused.)
8. Exam ine synchronizer assemblies for scoring, wear, or
other dam age. Replace synchronizers if not in first
class condition.
9. Inspect housings and covers for cracks, breaks, or
other dam age. Since repairs by welding, brazing, etc.,
are not recom m ended, replace all dam aged parts.
10. Inspect all bushings for wear or other dam age.
11. Check keys and keyways for condition and fit.
12. Inspect shift forks for Wear, distortion, or other
dam age.
13. Check springs for free length, com pressed length,
distortion, or collapsed coils.
REPAIR
Key num bers in text refer to Figure 2.
M a in s h a f t R e ar B e a rin g C a p
1. If inspection shows necessity, press or drive oil seal
assembly (28) out of rear bearing cap (27). Discard
oil seal.
2. Using a suitable sleeve and h am m er or press, drive or
press new oil seal (28) in bore of bearing cap (27). Lip
of oil seal goes in tow ard transm ission case.
ASSEMBLY OF SUBASSEMBLIES
T h e im p o r ta n c e of c le a n lin e ss c a n n o t be o v e re m ­
phasized. Rebuild of the transm ission should not be a t­
tem pted in a dirty w orking area. All parts, except those
being actually w orked on should be kept covered with
clean paper.
Avoid nicking, m arring, or burring all surfaces. W hene­
ver a com m on tool is specified, such as a “ soft” ham m er
or vise with “ soft-jaws,” that tool should be used. Subst-
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK S H O P M A N U A !