Chevrolet 10 Series 1970 Service Manual page 215

12. Replace the hose connections and install clam ps.
13. T e s t the operation of the shifting m echanism in a ll
speeds.
SHIFTER SPRING
Replacement
1. F o llo w instructions given in Steps 1, 2, 3, 4 under
"V acu um C ylin d er Diaphragm R ep la cem en t".
2. R em ove the piston rod fro m the housing.
3. Push in on end o f piston rod to re lie v e spring load
and rem ove snap ring fro m inside of piston rod. Pull
push rod assem bly out of piston rod.
4. P la c e head of push rod bolt in bench v is e and rem ove
two nuts, short spacer,
spacer, and stop washer fro m push rod bolt.
5. In stall stop w asher, long spacer, new spring, stop
washer and short spacer.
6. In stall adjusting nut on push rod and tighten until
distance between outer fa ces of stop w ashers is
2-13/16" (fig . 72).
7. In stall locknut on push rod and tighten, being carefu l
not to change the 2-13/16" adjustment.
8. Lu bricate inside of piston rod with engine o il and
in sta ll push rod assem bly.
9. Push in on push rod to com press spring and install
snap ring.
10. In stall push rod assem bly in the housing.
11. Com plete the assem bly o f the vacuum cylin der a c ­
cording to instruction given in Steps 5, 6, 7, 8, 9
under "V acuum C ylin d er Diaphragm Replacem ent" .
V A C U U M SHIFT CONTROL SWITCH
Replacement
The manually operated control switch, mounted on the
transm ission shift le v e r (fig . 73) is an electrom echanical,
tw o-p osition switch which con trols the axle vacuum shift
unit and the associated speedom eter adapter.
1. Disconnect switch e le c tr ic a l leads at the dash panel
mounted fuse block and speedom eter adapter.
2. R em ove the two screw s securing the axle shift con­
tro l va lve to the fram e
bracket.
F ig . 7 2 —A d ju s tin g Push Rod
stop washer, spring, long
side m em ber mounted
REAR SUSPENSION AND DRIVE LINE 4-39
F ig . 73—S h ift U n it C o n tro l S w itch
NOTE: Do not disconnect control va lve vacu­
um, atm osphere o r a ir clean er lines.
3. T ilt o r slide control va lve as requ ired to obtain a c ­
cess to cable retaining screw and disconnect cable
from valve (fig . 74). Disconnect conduit fro m valve
assem bly and rem ove
4. Rem ove the tran sm ission shift le v e r knob, then r e ­
m ove the two screw s
transm ission shift le v e r
housing assem bly from veh icle.
5. Make sure cable shift knob is in down position, then
attach switch housing rubber case on transm ission
shift le v e r so that the distance from top of cable shift
knob to top o f transm ission shift le v e r is 2-1/4".
Torque retaining screw s to 40 in. lbs.
transm ission shift le v e r knob.
6. Route cable to axle shift control v a lve, in sert control
cable into va lve assem bly and tighten conduit retain ­
ing fitting to 115 in. lbs.
7. Seat shoulder on control cable knob against housing,
then tighten set screw to retain cable and install
v a lv e -to -b ra c k e t retaining screw s.
8. Connect e le c tr ic a l leads to speedom eter adapter and
fuse block. Make sure a ll cable retaining clips are
secured.
T es t operation of shift system .
9 .
F ig . 74—V acuum C o n tro l S h ift C a b le Removal
a ll cable retaining clips.
retaining switch housing to
and withdraw cable and
R einstall
CHEVROLET TRUCK SERVICE MANUAL