Chevrolet 1980 Light Duty Truck Repair Manual page 355

Overhaul O perations........................................................... ..7B-9
Transmission D isassem bly................................................7B-9
M ainshaft D isassem b ly......................................................7B-12
Cleaning and In sp ection ................................................. ..7B-12
Transm ission C a s e .......................................................... ..7 B-12
Front and R ear Bearings................................................7B-13
R oller Bearings................................................................. ..7B-13
G ears..................................................................................... ..7B-13
T R A N S M IS S IO N D IS A S S E M B L Y
1. R em ove lower extension housing bolt and drain
transm ission (Fig. 7B-3B).
2. R em ove top cover and gasket from case.
3. R em ove long spring that retains the detent plug in
the case (Fig. 7B-4B). R em ove the detent plug w ith a sm all
m agnet.
4. R em ove extension housing and gasket.
5. Press dow n on speedom eter gear retainer and rem ove
speedom eter drive gear and retainer from output shaft.
6. R em ove fill plug from right side o f case (Fig. 7B-3B).
W orking through the plug opening drive out countergear
roll pin w ith a 3 /1 6 inch pin punch that has been cham fered
slightly.
D o not attem pt to retrieve pin at this time. Pin can
easily be retrieved after output shaft assem bly is removed.
7. Insert dum m y shaft tool J-25232 into bore at front
o f case, tap lightly on tool to push countershaft out rear o f
case (Fig. 7B-5B). With countershaft rem oved, allow
countergear to lie at bottom o f case.
8. Punch alignm ent mark in front bearing retainer and
transm ission case to ensure correct assem bly and rem ove
front bearing retainer and gasket (Fig. 7B-6B).
3 SPEED 7 7 M M TRANSMISSION
Fig. 7B-1 B-3-S peed 77 m m Transmission
M A N U A L TR A N S M IS S IO N
INDEX
R epairs.....................................................................................7B-14
Synchronizer K eys and Spring.....................................7B-14
Extension Oil Seal or B u sh in g .....................................7B-14
C lutch Bearing R etainer Qil Seal................................7B-14
M ainshaft A sse m b ly ........................................................... ..7 B-14
Transm ission A sse m b ly ..................................................... ..7 B-15
9. R em ove large locating snap ring from front bearing
and sm aller snap ring from clutch gear shaft.
10. R em ove clutch shaft front bearing using tool J-
6654-01 and tool J-8433-1 (Fig. 7B-7B).
It may be necessary to alternate the tightening o f the
bolts between tools J-6654-01 and J-8433-1 to rem ove the
front bearing.
11. R em ove large locating snap ring from rear bearing
and sm aller retaining snap ring from output shaft.
It may be necessary to place a screwdriver or a piece
o f bar stock between the case and the first-reverse sleeve and
gear assembly. This w ill hold the output shaft assem bly in
place w hile rem oving the rear bearing.
12. R em ove rear bearing from output shaft using tool
J -8 157-01 (Fig. 7B-8B).
13. R em ove set screw from First-R everse shifter fork
and slide shift rail out rear o f case.
14. Shift First-R everse sleeve and gear all the way
forward and rotate First-R everse shifter fork upward and
out o f case. R em ove First-R everse D etent plug from case.
15. Shift Second-Third Shifter fork rearward to gain
access to setscrew, rem ove setscrew, rotate shift rail 90° w ith
pliers to clear bottom detent plug and rem ove interlock plug
w ith m agnet (Fig. 7B-9B).
7B-9
OVERHAUL MANUAL