Chevrolet 1977 10 Series, Repair Manual, Page: 420 / 468

7B-40 OVERHAUL MANUAL
4-SPEED (MUNCIE CH465) 1 1 7 M M TRANSMISSION
INDEX
Disassembly of T ran sm issio n .............................................7B-40
Subassembly O p e ra tio n s......................................................7B-40
Transmission C o v e r......................................................... ..7B-40
D isassem bly........................................................................7B-40
A ssem bly.......................................................................... ..7B-40
Drive G e a r ......................................................................... ..7B-44
D isassem bly........................................................................7B-44
In sp e ctio n ......................................................................... ..7B-45
A ssem bly.......................................................................... ..7B-46
Drive G ear Bearing Retainer Oil Seal........................ 7B-46
M ainshaft............................................................................ 7B-47
Disassem bly...................................................................... 7B-47
In spection......................................................................... 7B-47
A ssem bly.......................................................................... 7B-48
C ountershaft....................................................................... 7B-49
Disassem bly...................................................................... 7B-49
A ssem bly.......................................................................... 7B-49
Assembly of Transm ission................................................ 7B-50
DISASSEMBLY OF TRANSM ISSION
Refer to Figures 7B-1L and 7B-2L
1. M ount transmission in suitable holding fixture and
remove cap screws attaching transmission cover assembly to
transmission case. If required, insert two 5/16 x 18 screws
in cover flange threaded holes and turn evenly to raise cover
dowel pins from case.
NOTE:
Move reverse shifter fork so that reverse idler
gear is partially engaged before attem pting to remove
cover. Forks must be positioned so rear edge of the slot
in the reverse fork is in line with the front edge of the
slot in the forward forks as viewed through tower
opening.
2. Place transmission in two gears at once to lock gears.
Remove the universal joint flange nut, universal joint front
flange and brake drum assembly.
NOTE:
On models equipped with 4-wheel drive
transm fer case, use Tool J-23070 to remove mainshaft
rear lock nut (Fig. 7B-26L).
3. Remove parking brake and brake flange plate
assembly on models equipped with propeller shaft parking
brake. Refer to Section 5, Truck Service Manual.
4. Remove rear bearing retainer and gasket.
5. Slide speedometer drive gear off mainsahft.
6. Remove drive gear bearing retainers and gasket.
7. Remove countergear front bearing cap and gasket.
8. Pry countergear front bearing out by inserting screw
drivers into groove at cast slots in case.
9. Remove countergear rear bearing retaining rings
(snap ring) from shaft and bearing. Using Tool J-22832 and
J-8433-1, remove countergear rear bearings (Fig. 7B-3L).
This will allow countergear assembly to rest on bottom of
case.
CAUTION: Make sure Tool J-22832 engages full
circumference o f groove in bearing to prevent tool
damage.
10. Remove drive gear bearing outer race to case
retaining ring.
11. Remove drive gear and bearing by tapping gently on
bottom side of drive gear shaft and prying directly opposite
against the case and bearing snap ring groove at the same
time. Remove 4th gear synchronizer ring.
CAUTION: Index cut out section o f drive gear in
down position with countergear to obtain clearance
for removing clutch gear.
12. Remove reaer mainshaft bearing retainer ring (snap
ring) and using Tool J-22832 and J-8433-1, remove bearing
from case (Fig. 7B-4L). Slide 1st speed gear thrust washer
off mainshaft.
13. Raise rear of mainshaft assembly and push rearward
in case bore, then swing front end up and lift from case.
Remove synchronizer cone from shaft.
14. Slide reverse idler gear rearw ard and move
countergear rearw ard until front end is free of case, then lift
to remove from case.
15. To remove reverse idler gear, drive reverse idler gear
shaft out of case from front to rear using a drive. Remove
reverse idler gear from case.
SUBASSEMBLY OPERATIONS
TRANSM ISSIO N COVER
Disassembly (Fig. 7B-5L)
1. Using a small punch drive out pins retaining lst-2nd
and 3rd-4th shifter forks to shifter shafts and also drive out
expansion plugs.
NOTE:
The pin retaining the third and fourth shifter
fork to the shaft must be removed, and the shifter fork
removed from the cover before the reverse shifter head
pin can be removed.
2. With shifter shafts in neutral position, drive shafts out
of cover and shafter forks.
CAUTION: Exercise care so shaft detent balls,
springs and innerlock pin located in the cover are
not lost as the shifter shafts are removed.
3. Drive out pin holding reverse shifter head and drive
out the shaft.
CAUTION: Exercise extreme care during shaft
removal since detent balls are under spring tension
in the rear rail boss holes.
Assembly (Fig. 7B-6L)
1. In reassembling the transmission cover, care must be
used in installing the shifter shafts. They should be installed
in the order shown in Fig. 7B-7L, namely, reverse, 3rd-4th,
and lst-2nd. Fig. 7B-6L illustrates the difference in the shafts.