Chevrolet 70 1969 Series, Shop Manual

Page: 821 / 913

TRANSMISSION AND CLUTCH 7-75
(41), engaging lock with slot in shaft. Secure lock to
shaft with bolt and lock washer. Tighten bolt firmly.
M A IN S H A F T IN ST A L L A T IO N
1. Position m ainshaft 1st speed gear and bushing assem ­
bly (54) and reverse gear (53) in transm ission case (6).
2. Install m ainshaft assembly (52) in transm ission case
by tilting rear end of the assem bly down and lowering
into and through reverse gear (53), 1st speed gear
(54), and opening in rear of case. Use care while
meshing splines on shaft with teeth on reverse gear
(53). Lower front end of m ainshaft in line with pilot
bearing opening in case and move the assem bly for­
ward into proper position. Refer to Figure 8.
3. Install pressure rotor backing plate (48) on the main
drive gear shaft (51).
4. Position pressure rotor drive pin (71) on drive gear
shaft (51).
5. Install pressure rotor (47) on drive gear shaft (51).
IM P O R T A N T : S id e o f rotor m a rk e d F R O N T go e s
to w a r d
front of
tran sm issio n a w a y
from
the
b a c k in g plate. W ith rotor d rive pin (7 1 ) a t the
to p a n d v a n e slot in rotor a t bottom , check for
oil inlet hole in the rotor. T his hole m u st b e on
left sid e of rotor v a n e slot, or w ith the drive
g e a r tu rn in g in a clockw ise direction, oil inlet
hole m u st be a h e a d of the rotor v a n e . Install
rotor v a n e (7 0 ) (fig . 2 8 ).
6. Position new O-ring seal (69) in groove in pressure
rotor backing plate (48).
7. Install main drive gear bearing cap (46) on m ain drive
gear (51).
IM PO RT A NT : O il inlet a n d oil outlet holes m ust
a lig n b e tw e e n rotor b a c k in g p late (4 8 ) a n d
d rive g e a r b e a rin g c a p (4 6 ). A lig n w o r d T O P
on c a p w ith T O P on b a c k in g plate.
8. Position main drive gear (51), backing plate (48),
drive gear bearing cap (46), pressure rotor (47), and
new gasket in transm ission case so the main drive
gear (51) engages and m eshes with the countershaft
drive gear (33).
IM P O R T A N T : O il inlet a n d outlet holes m ust
line u p w ith oil holes in tran sm issio n case a n d
the w o r d T O P on b e a r in g c a p to w a rd top of
tran sm issio n case.
9. Install four bolts and lock washers. Tighten bolts
firmly.
10. Install m ainshaft 1st speed gear thrust washer (20);
then using a suitable installer sleeve and ham m er, in­
stall m ainshaft rear bearing (19) on rear end of m ain­
shaft (52).
11. Lock transm ission gears into two speeds at the same
time and tighten countershaft rear bearing retaining
nut (8). D raw nut up tight; then stake in position with
ham m er and punch.
NOTE:
The retainer nut (8) w a s pre viou sly in ­
stalled loosely in step 4 in cou n tersh aft in sta lla ­
tion.
12. Position speedom eter drive gear (10) on rear end of
m ainshaft (52).
13. If not previously installed, install new m ainshaft rear
bearing cap oil seal (12), using a suitable sleeve and
ham m er.
NOTE: Lip o f oil se a l g o e s to w a r d front o f b e a r­
in g cap.
14. Install m ainshaft (11) and countershaft (9) rear
bearing caps and new gaskets^ Tighten bolts firmly.
15. With transmission still “ locked up." install propeller
shaft brake com panion flange (13) and retainer nut
(14) on rear end of m ainshaft. Tighten nut to 250
foot-pounds torque; then install new cotter pin.
16. Install speedom eter driven gear (16) and adapter
(15) in m ainshaft rear bearing cap (11) meshing teeth
of drive and driven gears.
17. Install P.T.O. covers (2) and new gaskets (3). Tighten
attaching bolts firmly.
18. Install drain and filler plugs (2! and 5). Tighten
plugs securely.
19. Install the pressure rotor oil gallery m agnetic plug
(24) in transm ission case. Tighten plug firmly.
20. If not previously installed, install clutch housing (I)
on transm ission case attaching with four stud nuts
and lock washers. Tighten stud nuts securely.
SHIFT B A R H O U S IN G IN ST A LL A T IO N
1. W ith transm ission in “ N eutral,” install shift bar
housing on transm ission case, attaching with eleven
bolts and lock washers. Tighten bolts firmly.
2. Install control top oil baffle and two new gaskets, one
over and one under the oil baffle.
3. Install transm ission propeller shaft brake parts.
4. C heck to be sure transm ission is in “ N eu tral,” by
holding brake drum and turning main drive gear.
C O N T R O L T O W ER IN ST A L LA T IO N
N O T E : O n tran sm issio n s h a v in g a co n ve n tio n al
g e a rsh ift lever, accom p lish the fo llo w in g proce­
dures:
1. W ith transm ission in “ N eutral,” position a new gas­
ket on shift bar housing.
2. Install control tower on shift bar housing, attaching
with four bolts and lock washers. Tighten bolts se­
curely.
CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L