ENGINE-ELECTRICAL 6Y-29
each capacitor (not illustrated). The capacitor is
shorted if both readings are zero.
6. Resistor Rl: The resistor is open if both readings
are infinite.
7. Resistor R2: Use an ohmmeter scale on which the
1800 ohm value is within, or nearly within, the
middle third of the scale. If both readings are infi-
nite, the resistor is open.
8. Resistor R3: Use an ohmmeter scale on which the
680 Ohm value is within, or nearly within, the middle
third of the scale. If both readings are infinite, the
resistor is open.
9. Resistor R4: Select an ohmmeter scale on which the
15000 ohm value is within, or nearly .within, the
middle third of the scale. If either reading is infi-
nite, the resistor is open. ~
10.
Resistor R5: Use the lowest range ohmmeter scale.
The resistor is open if either reading is infinite.
NOTE:
This resistor on some applications may
be located in the vehicle wiring harness, and not
on the panel board.
11.
Resistor R6: An ohmmeter scale on which the 150
ohm value is within or nearly within, the middle
third of the scale should be used. If both readings
are infinite, the resistor is open.
REASSEMBLY
During assembly, coat with silicone grease both sides
of the flat insulators used between the transistors and
heat sink, and also the heat sink on the side on which the
transistors are mounted. The silicone grease, which is
available commercially, conducts heat and thereby pro-
vides better cooling.'
IGNITION PULSE AMPLIFIER
R-5
C-3 Ju
MAGNETIC PULSE
DISTRIBUTOR
IGNITION SWITCH REPLACEMENT (Figs.
21
i to 23i)
CHEVROLET, CHEVY II AND CORVETTE
1.
Raise hood and disconnect battery ground cable from
battery.
2.
Remove lock cylinder by positioning switch in "off"
position and inserting wire in small hole in cylinder
face. Push in on wire to depress plunger and con-
tinue to turn key counter-clockwise until lock cylin-
der can be removed.
3.
Remove the metal ignition switch nut from the pas-
senger side of the dash using Tool J-7607 (Fig. 21i).
4.
Pull the ignition switch out from under the dash and
remove the wiring connectors.
5. To remove the "theft resistant" connector, the
switch must be out from under the dash as outlined
in Step 4. Using a screw driver unsnap the locking
tangs on the connector from their position on the
switch as shown in Figure 22i. Unplug the connector.
6. Snap the connector into place on a new ignition
switch.
7. Place the switch into position from behind the dash
and install the metal ignition switch nut.
8. Install the lock cylinder.
9. Install the battery cable to the battery and lower the
hood.
CHEVELLE
1.
Disconnect battery ground cable.
2.
Remove ash tray, retainer attaching screws and
retainer.
3.
Remove A/C distributor duct retaining screws and
duct.
Fig.
19i—Pulse Amplifier Internal Circuitry
Fig.
20i—Transistor Checking
CHEVROLET Oi
ENGINE-ELECTRICAL-6Y-30
Fig.
2 li—Removing Ignition Switch Nut
4.
Remove heater and/or A/C control panel assembly
retaining screws and push panel assembly from
console.
NOTE: If interference between control panel
and radio is encountered, loosen radio retaining
nuts.
5.
Remove radio control knobs, bezels and retaining
nuts.
6. Disconnect radio wiring harness and antenna lead-in.
7.
Remove radio rear brace attaching screw and re-
move radio from vehicle.
Fig.
231—Switch and Connector Unplugged
8. Remove ignition switch bezel nut using Tool J-7607
and push switch rearward from panel opening.
9. Disconnect wiring connector from rear of switch.
10.
To install, reverse removal procedure.
SPARK PLUGS
CLEANING AND REGAPPING
Clean the spark plugs thoroughly, using an abrasive-
type cleaner. If the porcelains are badly glazed or
blistered, the spark plugs should be replaced. All spark
plugs must be of the same make and number or heat
range. Use a round feeler gauge to adjust the spark plug
gap to specifications (fig. 24i).
Fig.
22i—Unlocking Ignition Switch Connector
Fig.
241—Setting Sfxirk Plug Gap
CHEVROLET CHASSIS SERVICE MANUAL
ENGINE-ELECTRICAL 6Y-32
STARTER CIRCUIT
INDEX
Page
General Description 6Y-32
Maintenance and Adjustments . '. . 6Y-32
Resistance Checks 6Y-32
Starting Motor and Solenoid Check 6Y-33
Page
Service Operations 6Y-33
Starter Motor 6Y-33
Removal and Installation 6Y-33
GENERAL DESCRIPTION
The function of the starting system, composed of the
starting motor, solenoid and battery, is to crank the
engine. The battery supplies the electrical energy, the
solenoid completes the circuit to the starting motor, and
the motor then does the actual work of cranking the
engine.
The starting motor (fig. Is) consists primarily of the
drive mechanism, frame, armature, brushes, and field
windings. The starting motor is a pad mounted 12-volt
extruded frame type, having four pole shoes and four
fields,
connected with the armature. The aluminum drive
end housing is extended to enclose the entire shift lever
and plunger mechanism, protecting them from dirt,
splash, and icing. The flange mounted solenoid switch
operates the overrunning clutch drive by means of a
linkage to the shaft lever.
The V-8 wiring harness differs from the in-line engine
in that the ignition lead to the coil from the switch is at-
tached at the coil instead of at the starter solenoid (fig.
2s).
CONTACT
FINGER
PINION
STOP
BRUSH
INSULATED BRUSH HOLDER \ FIELD COIL
BRUSH SPRING ARMATURE
GROUNDED BRUSH HOLDER
OVERRUNNING
CLUTCH
Fig.
Is—Starting Motor Cross Section (Typical)
MAINTENANCE AND ADJUSTMENTS
No periodic lubrication of the starting motor or sole-
noid is required. Since the starting motor and brushes
cannot be inspected without disassembling the unit, no.
service is required on these units between overhaul
periods.
RESISTANCE CHECKS
Although the starting motor cannot be checked against
specifications on the car, a check can be made for. exces-
sive resistance in the starting circuit. Place a volt-
meter across points in the cranking circuit as outlined
below and observe the reading with the starting switch
closed and the motor cranking (distributor primary lead
grounded to prevent engine firing).
1.
From battery positive post To solenoid battery
terminal.
CHEVROLET CHASSIS SERVICE MANUAL
ENGINE-ELECTRICAL 6Y-34
SPECIAL TOOLS
J-7607
IGNITION SWITCH
NUT REMOVER
J-9717-2
SUPPORT
TOOL
J-9717-1
PRESS
TOOL
J-9600-2
SHOULDERED
INSTALLER
J-21501
PULLY
ADAPTER
J-5184
CHECKING
SCALE
J-21600
HARNESS ADAPTER
Fig. 4s-Specia! Tools
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-9
6. Connect speedometer cable.
7. Install propeller shaft assembly.
8. Fill transmission with lubricant specified in Section
O.
CORVETTE TRANSMISSION REPLACEMENT
, 1. Disconnect battery ground cable.
2.
Pisassemble transmission shift control lever by un-
screwing ball from lever, lifting out
"T"
handle re-
turn spring and "T" handle, then remove the anti-
rattle bushings.
3.
Raise front and rear of vehicle.
4.
Insert a block of wood between the top of the dif-
ferential carrier housing and the underbody (to pre-
vent upward travel of the carrier when the carrier
front support is disconnected).
5. Disconnect the differential carrier front supportfrom
its frame bracket, by removing the nut on the under-
side of the biscuit mount.
6. Pry the carrier downward to relieve load while re-
moving the two center mounting bolts from the car-
rier front support. (To pry carrier downward insert
crowfoot end of a pry bar through the opening in the
carrier front support, hooking end of bar over top of
the center mounting bolt pad cast in the underside of
the carrier.)
7. Pivot carrier support downward for access to prop
shaft "U" joint.
8.
.
Disconnect prop shaft front and then rear "U" bolts.
9. Disconnect parking brake cable from ball socket at
idler lever located near center of underbody.
10.
Remove prop shaft by moving shaft forward.
11.
Remove heat deflectors from the right and left ex-
haust pipe.
12.
Remove left bank exhaust pipe.
13.
Remove right bank exhaust pipe and heat riser.
14.
Disassemble the transmission mount, as follows:
a. Remove the two bolts that attach rear mount
cushion to the rear mount bracket.
b.
Support engine under oil pan and raise engine to
remove load from rear mount cushion.
CAUTION: To avoid damage to oil pan, a suit-
able wide base, heavy wood platform should be
placed between the jack pad and the oil pan.
c. Remove the three transmission mount bracket-
to-
crossm ember bolts and remove mount bracket.
d. Remove the two bolts from mount pad to trans-
mission case and remove rubber mount cushion
and exhaust pipe "yoke".
15.
Disconnect transmission linkage by removing the
shift levers at the transmission side cover.
16.
Disconnect speedo cable at transmission extension.
17.
Remove transmission output shaft slip yoke.
NOTE:
The yoke is removed to avoid tearing
the heat reflecting pad on the underbody, when
the transmission is being removed.
18.
Remove two bolts to disconnect the transmission
gearshift control lever and bracket assembly from
its adapter plate on side of transmission. Lower
transmission assembly from the vehicle, letting the
gearshift lever slide down and through the dust boot
in the console.
19.
Remove transmission-to-clutch housing attaching
bolts.
20.
Slide transmission assembly rearward from clutch
and rotate transmission for access to the three flat
head machine screws in the control lever bracket
adapter plate. Remove adapter plate. Rotate trans-
mission back to the upright position.
21.
To allow room for transmission removal slowly
lower the rear of engine until the tachometer drive
cable at the distributor just clears the horizontal
ledge across the front of dash.
CAUTION: The tachometer cable can be easily
damaged by heavy contact with the dash. Slide
transmission rearward out of the clutch, then
tip front end of transmission downward and
lower the assembly from vehicle.
22.
Reinstall transmission assembly by performing above
steps in reverse order.
TRANSMISSION OVERDRIVE
INDEX
Page
General
Description 7-10
Maintenance
and Adjustments 7—10
Governor
Switch and Pinion .............. 7-10
Sun
Gear Solenoid Oil Seal and Control
Cable
Bracket 7-10
Case
Rear Oil Seal 7-10
Removal
7-10
Installation
. . . . . 7-10
Control
Shaft Lever and Oil Seal 7-10
Speedometer
Driven Gear 7-10
Electrical
Unit Checks 7-11
Overdrive
Relay . 7-11
Page
Air
Gap 7-11
Point
Opening 7-11
Closing
Voltage 7-11
Solenoid
. 7-11
Closing
Coil 7-11
Engaging
Spring . - 7-11
Ignition
Grounding Contact . 7-11
Governor
Switch 7-11
Kickdown
Switch 7-11
Diagnosis
- Overdrive 7-12
Mechanical
. 7-12
Electrical
7-13
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-11
UPPER ARMATURE STOP
(BEND TO ADJUST POINT OPENING)
Fig.
2B-Adjusting Relay Point Opening
ELECTRICAL UNIT CHECKS
Overdrive Relay
Specifications and checking procedures for this relay
are as follows:
Specifications
Air Gap Oil inch minimum
Point Opening .025 inch
Closing Voltage
8.3-10.2
volts
Armature Sealing Voltage. ..... 11.2 volts maximum
Three checks and adjustments are required on the
overdrive relay; air gap, point opening and closing volt-
age.
The air gap contact point opening checks and adjust-
ments should be made with the battery disconnected.
Air Gap
The air gap should not normally require adjustment
unless the relay has been misadjusted. Check the air gap
with the points barely touching and adjust if necessary by
bending the lower point support (fig, IB).
Point Opening
Check the contact point opening and adjust by bending
the upper armature stop (fig. 2B).
Closing Voltage
To check the relay closing voltage, connect a potenti-
ometer or variable resistance of sufficient value (not less
than 50 ohms) in series with the "KD" terminal, connect a
voltmeter to the "IGN" and "KD" terminals. With the
ignition switch on, slowly decrease the amount of resist-
ance in order to check the relay closing voltage (the
overdrive solenoid and relay should click when the relay
closes). Adjust the closing voltage by bending the arma-
ture spring post (fig. 3B). Bend down to increase the
closing voltage and bend up to decrease the closing
voltage.
To check the sealing voltage, increase the voltage after
the relay closes until the armature seals against the
core.
Decrease the sealing voltage by reducing the relay
air gap.
Solenoid
Closing Coil
Remove solenoid from transmission, connect a jumper
wire between negative terminal of battery and mounting
flange of solenoid. Connect a second jumper wire be-
ARMATURE SPRING PQST
(BEND TO ADJUST CLOSING VOLTAGE)
Fig.
3B - Adjusting Relay Closing Voltage
tween the battery positive terminal and solenoid terminal
No.
4; this should cause the solenoid pawl to move out.
If solenoid chatters, Hold-In Coil is defective.
Engaging Spring
With jumper wire connected as in paragraph above,
(solenoid energized, plunger extended) place ball end of
solenoid against bench. Push down on solenoid. The
pawl rod should move in 3/8M under a load of not less
than 8 lbs. nor more than 12. Pawl should move out to
extended position when load is removed.
Ignition Grounding Contact
Place a test lamp between negative battery terminal
and solenoid terminal No. 6. Lamp should light when this
connection is made. Remove jumper from between nega-
tive battery terminal and solenoid terminal No. 4. Pawl
rod should snap "in" and test lamp should go out.
Governor Switch
Remove overdrive wire at governor and connect test
lamp between governor overdrive terminal and positive
terminal of battery. Drive car on road or raise on jacks.
The lamp should light at a car speed of between 26 to 30
MPH. Upon decreasing speed, the lamp should go out at
between 28 and 23.5 MPH. The car speed differential
between light "on" and light "off" should be 2 or 3 MPH.
Kickdown Switch
Disconnect the 4 wires at kickdown switch.
1.
Connect test lamp between "SW" terminal and posi-
tive terminal of battery; with switch in normal posi-
tion, lamp should light when "REL" terminal is
grounded but should not light when "IGN" or "SOL"
terminals or switch case is grounded.
2.
Connect test lamp between "IGN" terminal and posi-
tive terminal of battery; with switch stem pushed in,
lamp should light when "SOL" terminal is grounded,
but should not light when "SW" or "REL" terminals
or switch case is grounded.
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-12
DIAGNOSIS-OVERDRIVE
MECHANICAL
Any one of the following general complaints may be due
to non-standard mechanical conditions in the overdrive
unit:
1.
Does not drive unless locked up manually.
2.
Does not engage, or lock-up does not release.
3.
Engages with a severe jolt, or noise.
4.
Free-wheels at speeds over 30 mph.
These^ troubles may be diagnosed and remedied as de-
scribed in the following paragraphs.
1.
Does not drive unless locked up manually.
a. Occasionally, the unit may not drive the car for-
ward in direct drive, unless locked up by pulling
the dash control. This may be caused by one or
more broken rollers in the roller clutch, the
remedy for which is the replacement of the entire
set of rollers.
b.
This may also be caused by sticking of the roller
retainer upon the cam. This retainer must move
freely to push the rollers into engaging position,
under the pressure of the two actuating springs.
c. Sometimes this is due to slight indentations, worn
in the cam faces by the rollers spinning, remedied
by replacement of the cam.
2.
Does not engage, or lock-up does not release
.. a. Dash control improperly connected—-Unless the
overdrive dash control wire is connected to the
lockup lever on the left side of the overdrive
housing in such a manner as to move the lever
all the way back when the dash control knob is
pushed in, it may hold the shift rail in such a po-
sition as to interlock the pawl against full engage-
ment resulting in a buzzing noise when overdrive
engagement is attempted.
To correctly make this connection, loosen bind-
ing post at lever, pull dash control knob out 1/4",
move lever all the way to the rear, and tighten
binding post.
b.
Transmission and overdrive improperly aligned—
The same symptoms as above may also result
from misalignment, at assembly, of the overdrive
housing to the transmission case, resulting in
binding of the overdrive shift rail, so that the re-
tractor spring cannot move the rail fully forward,
when the dash control knob is pushed in, and the
transmission is not in reverse. Under such con-
ditions, the unit may remain fully locked up.
To test for this, be sure that the transmission
is not in reverse; disconnect the dash control
wire from the lockup lever, and feel the lever for
free forward movement. If the lever can be
moved forward more than 1/4", it indicates that
misalignment probably exists. To correct this,
Jposen the capscrews between the overdrive hous-
ing and transmission case, and tap the adpater
plate and overdrive housing until a position is
found where the rail shifts freely; tighten cap-
screws.
c. Kickdown switch improperly adjusted—The posi-
tion of the kickdown switch should be adjusted,
by means of the two large nuts which clamp the
switch shank, so the switch plunger travels 3/16"
before the throttle lever touches its stop.
Occasionally the large nuts which clamp the
switch through the switch bracket are tightened
sufficiently to bend the switch shank, thus pre-
venting free motion of the switch stem. This may
usually be remedied by loosening the upper of the
two nuts.
d. Improper installation of solenoid—If car cannot
be rolled backward under any circumstances and
there is no relay click when the ignition is turned
on, it probably indicates that the solenoid has
been installed directly, without twisting into the
bayonet lock between solenoid stem and pawl, thus
jamming the pawl permanently into overdrive en-
gagement. If the car will occasionally roll back-
wards, but not always, (and there is no relay click
when the ignition switch is turned on) it may indi-
cate that, upon installation, the bayonet lock was
caught, and the solenoid forcibly twisted into
alignment with the attaching flange, thus shearing
off the internal keying of the solenoid. Under
these circumstances, the end of the solenoid stem
may not catch in the pawl, and upon release of the
solenoid, the pawl will not be withdrawn promptly
from engagement, but simply drift out. If the
solenoid stem end has its two flats exactly facing
the two solenoid flange holes, it will not withdraw
the pawl properly. If the stem can be rotated
when grasped by a pair of pliers, it indicates that
the internal keying has been sheared.
e. Improper positioning of blocker ring—Occasion-
ally, either in assembly at the factory, or in
service operations in the field, the internal parts
of the overdrive unit may have been rotated with
the solenoid pawl removed, causing the blocker
ring to rotate, so that its two lugs are not located
with respect to- the pawl as shown in Figure 12B.
In other words, the solid portion of the blocker
ring may be in alignment with the pawl, which will
prevent fill} engagement of the pawl with the sun
gear control plate/
To test for this condition, remove solenoid
cover, pull dash control knob out, roll car 2 ft.
forward. Push dash control in, turn ignition
switch on. Then ground the "KD" terminal of
relay, and watch movement of center stem of
solenoid. It should not move more than 1/8" when
the solenoid clicks. Then, with the relay terminal
still grounded, shift into low gear, and roll car
forward by hand. Solenoid stem should then move
an additional 3/8", as the pawl engages fully.
These two tests indicate proper blocker action.
Unless both tests are met, the blocker ring is
probably not in the correct position.
3.
Engages with a severe jolt or noise
Insufficient blocker ring friction may cause the ring
to lose its grip on the hub of the sun gear control
plate. Check the fit and tension of the ring as de-
scribed under "Cleaning and Inspection".
4.
Free-wheels at speeds over 30 MPH
If cam roller retainer spring tension is weak the unit
will free wheel at all times. Check spring action as
described under "Cleaning and Inspection".
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-13
PULL-IN
WINDING
li
HOLD-IN
WINDING
Fig.
4B -
Overdrive Electrical Circuit Wiring Diagram
ELECTRICAL
Any one of the following general complaints may be due
to electrical trouble in the overdrive circuit.
1.
Does not engage.
2.
Does not release.
3.
Does not kickdown from overdrive.
These troubles may be traced and remedied as de-
scribed in the following paragraphs.
1.
Does not engage
a. With the ignition switch on, ground the "KD" ter-
minal of the solenoid relay with a jumper lead.
If the solenoid clicks, the relay and solenoid cir-
cuits are in operating condition. If no click is
heard in the relay, check the fuse and replace if
defective.
b.
If the fuse is good, use a second jumper lead to
connect the "SOL" and "BAT" terminals of the
relay. If a click is now heard in the solenoid, the
relay is probably at fault and should be repaired
or replaced.
c. If the solenoid does not click in Step b, check the
wiring to the No. 4 terminal of the solenoid and
replace if necessary. If the wiring is not defec-
tive,
the trouble is probably in the solenoid. Re-
move the solenoid cover, examine the solenoid
contacts in series with the pull-in winding and
clean if necessary. Test again for clicks, as in
Step b, after replacing solenoid cover and lead
wires.
Replace the solenoid if trouble has not
been corrected.
d. If the relay and solenoid circuits are in good con-
dition as determined in Step a, leave the ignition
switch on and make sure the manual control knob
is in the overdrive position. Ground one and then
the other of the two terminals next to the stem of
the kickdown switch (identified as "SW" and
?fREL"). K the solenoid clicks when one terminal
is grounded but not the other, replace the switch.
If the solenoid does not click when either of the
terminals is grounded, check the wiring between
the relay and the kickdown switch and replace if
defective.
e. If the solenoid clicks as each terminal is grounded
in Step d, ground the governor switch terminal.
If the solenoid clicks, the governor switch may be
defective. If the solenoid does not click, check
the wiring between the kickdown and governor
switches and replace if necessary.
2.
Does not release
a. Remove the connection to the "KD" terminal of
the relay. If this release overdrive, look for a
grounded control circuit between the relay and
governor switch.
b.
If the overdrive is not released in Step a, dis-
connect the lead to the "SOL" terminal of relay.
If this releases the overdrive, replace the relay.
3.
Does not kickdown from overdrive
a. With the engine running, connect a jumper lead
between the No. 6 terminal of the solenoid and
ground. Operate the kickdown switch by hand.
This should stop the engine. If it does, the sole-
noid is probably defective and it should be checked
for dirty ground-out contacts or other defects
within the ground-out circuit of the solenoid (fig.
4B).
Clean the contacts or replace the contact
plate as required.
b.
If the engine does not stop in Step a, ground one
and then the other of the two terminals (Identified
as "IGN" and "SOL") farthest from the sfem of
the kickdown switch. The engine should stop when
one of the two terminals (IGN) is grounded. If
the engine does not stop when the terminal is
grounded, the wiring or connections to the switch
between the switch and coil are defective. When
the btlier terminal (SOL) is grounded, the engine
should stop when the kickdown switch is operated.
If the engine does not stop when the kickdown
switch is operated with the second terminal
grounded, the kickdown switch is defective. If
the trouble is in the kickdown switch, adjust the
linkage to give more travel of the switch rod.
If this does not correct the trouble, replace the
kickdown switch.
If the kickdown switch operates as it should,
check for an open circuit in the wiring between
the kickdown switch and the No. 6 terminal of the
solenoid.
c. If the trouble is not located by the above checks,
the upper contacts of the kickdown switch may not
be opening. To check for this condition, ground
the overdrive control circuit at the governor
switch. This should cause the solenoid to click.
Operate the kickdown switch by hand. This should
cause a second click as the solenoid releases.
If there is no second click, adjust the linkage to
give more travel of the switch rod. If this does
not correct the trouble, replace the kickdown
switch.
CHEVROLET CHASSIS SERVICE MANUAL