Chevrolet 10 Series 1970, Service Manual

Page: 214 / 671

REAR SUSPENSION AND DRIVE LINE 4-38
Assembly
1. Install autom atic switch assem bly into housing using
flat head s c re w to attach switch to housing. On out­
side o f housing, in stall insulator, and jam nuts on
switch term in al sc re w s . Tighten nuts fir m ly .
2. P o sitio n m otor c o v e r gasket on housing and in sert
m otor (with c o v e r ) into housing. Install cable clip
and the three c o v e r screw s and lock w ashers.
Tighten s c rew s fir m ly .
3. Attach m otor w ire s to switch term in a ls. The longer
w ire attaches to bottom term in al. Tighten term in al
nuts.
4. W ith a s c re w d r iv e r in serted into slot o f d rive
s crew , in stall bearin g on end o f s crew with shielded
side o f bearin g tow ard inside as shown in Figu re 69.
R etain bearin g with b earin g locknut.
5. Run d riv e nut to center o f d riv e screw , then in sert
slotted end o f screw into housing, m eshing slotted
end with arm atu re shaft.
NOTE: F ib e r bumper contact on d riv e nut must
be toward switch.
6. Install b earin g gasket and co v e r with three screw s
and lock w ash ers. Tighten screw s secu rely.
7. If the assem bly consisting o f shift fo rk actuating
le v e r , torsion spring and spring winding le v e r has
been separated, rea ssem b le in the follow in g manner.
P la c e shift fo rk actuating le v e r in v is e , turn the
spring winding le v e r with one end o f spring, in clo ck ­
w ise d irection until end o f spring is past shift fork
actuating le v e r ; then push le v e r inward until the
spring is locked in p lace.
8. Dip above a ssem b ly in SAE 10 engine o il. W ith d rive
nut on d riv e s crew assem bly in center o f screw ,
and fib e r contact bum per down toward switch, p o­
sition the slots o f winding le v e r o v e r the d riv e nut.
Install the le v e r shaft through center o f assem bly
into depression in housing.
9. Install front co v e r gasket on housing. Install housing
fron t c o v e r with detent spring against d riv e nut. A t ­
tach co v e r secu rely with screw s and lock w ashers.
Installation
1. Check the two lead w ir e s on the housing term in als.
2. W ith the seal between the c a r r ie r and shift unit po­
sitioned c o rre c tly ; slid e the shift unit on the d iffe r ­
ential c a r r ie r studs with the torsion spring sw ivel
block in serted in the shift fo rk slot.
3. In stall the stud nuts, tightening to 50-70 foot-pounds
torque.
4. F ill the shift unit to operating capacity with lubricant
as sp ecified under "G e n e r a l Maintenance” .
5. Check installation by making a " L O ” and " H I ” range
shift. Ignition must be turned on b e fo re check can be
made.
NOTE: The shift unit m otor runs equally w ell
in eith er d irection , h ow ever, i f the lead w ire s
a re r e v e rs e d at the term in a ls on the shift unit,
the axle w ill shift to the opposite range o f that
indicated on the con trol switch.
6. Connect w ire at plug.
V A C U U M CYLINDER D IA P H R A G M
Replacem ent
1. R em ove clam ps on hose connections at the vacuum
cylin d er and slip hoses o ff the connecting fittin gs.
2. R em ove the three retaining bolts and lock washers
retaining the vacuum cylin d er assem bly to the d if­
feren tia l c a r r ie r housing and rem ove the vacuum
cylin d er assem bly fro m the veh icle.
3. R em ove the s c rew s that attach the two halves o f the
vacuum cylin d er and rem ove the outer half.
4. Using two 1/2" open end w renches, one to hold the
push rod inner nuts and the other to rem ove the outer
nut fro m the push rod, rem ove the diaphragm plates
and diaphragm.
5. Install new diaphragm and plates to push rod and
tighten the retaining nut secu rely.
NOTE: A pply P e rm a te x o r equivalent around
push rod hole between diaphragm plates.
6. A ssem b le outer half o f vacuum cylin d er to inner half,
install retaining s c re w s and tighten secu rely.
7. Install a new gasket and install the vacuum sh ifter
assem bly on the d iffe re n tia l c a r r ie r housing.
8. R eplace hose connections and install clam ps.
C A U TIO N : Be carefu l not to transpose hose
connections.
9. T e s t operation o f shifting m echanism in a ll speeds.
V A C U U M CYLINDER OIL SEAL
Replacem ent
1. Rem ove clam ps fro m hose connections and rem ove
hoses fro m fittings.
2. R em ove the three lo w er retaining b olts and lock
w ashers that attach the vacuum cylin d er to the d if­
feren tia l c a r r ie r housing and rem ove the vacuum
c ylin d er
assem bly fro m the d iffe re n tia l c a r r ie r
housing.
3. R em ove the two retaining bolts and lock w ashers at­
taching the vacuum cylin d er to its housing and sepa­
rate the two a ssem b lies.
4. R em ove the screw s that attach the two halves o f the
vacuum cylin d er and rem ove the outer half.
5. R em ove the diaphragm plates, and shaft as an
assem bly.
6. D riv e the old seal out o f the housing.
7. Soak new seal in engine o il to p rovid e fo r in itial lu ­
b rication . Coat outer diam eter o f seal with P e r m a ­
tex o r equivalent and rep lace it in the inner half o f
the cylin d er with the fr e e side o f the seal lip down
and p re s s it into place with seal in sta ller T o o l
J-0968.
8. A ssem b le the diaphragm shaft assem bly into the
housing.
9. Install the outer c o v e r, and retaining screw s.
C A UTIO N: Install the co v e r with the vacuum
line connection aligned with the connection on the
lo w e r outer c o ver.
10. A ssem b le the vacuum cylin d er assem b ly into its
housing, install the two retaining b olts and lock
w ashers and tighten secu rely.
NOTE: The fe lt seal and fe lt seal in the housing
should be inspected fo r damage and replaced
when n ecessary.
11. Install the com pleted assem bly to the c a r r ie r housing
with new gasket and the three retaining bolts and lock
w ashers and tighten secu rely.
CHEVROLET TRUCK SERVICE MANUAL