ignition CHEVROLET CAMARO 1967 1.G Chassis Owner's Guide

ENGINE-ELECTRICAL 6Y-27

timing mark on pulley lines up with timing tab.

2.
Position distributor to opening in block in normal

installed attitude (fig. 15i), noting position of vacuum

control unit.

3.
Position rotor to point toward front of engine (with

distributor housing held in installed attitude), then

turn rotor counter-clockwise approximately 1/8 turn

more toward left cylinder bank and push distributor

down to engine camshaft. It may be necessary to ro-

tate rotor slightly until camshaft engagement is felt.

4.
While pressing firmly down on distributor housing,

kick starter over a few times to make sure oil pump

shaft is engaged. Install hold-down clamp and bolt

and snug up bolt.

5. Turn distributor body slightly until points just open

and tighten distributor clamp bolt.

6. Place distributor cap in position and check to see

that rotor lines up with terminal for No. 1 spark

plug.

7. Install cap, check all high tension wire connections

and connect spark plug wires if they have been re-

moved. It is important that the wires be installed in

their location in the supports.

NOTE:
The brackets are numbered to show the

correct installation. Wires must be installed as

indicated to prevent cross firing.

8. Connect vacuum line to distributor and distributor

primary wire to coil terminal.

9. Start engine and set timing as described under Turn-

Up in Section 6.

BREAKERLESS (MAGNETIC PULSE)

DISTRIBUTOR

REMOVAL (CORVETTE)

1.
If vehicle is equipped with radio, remove three bolts

securing ignition shield over distributor and coil.

One bolt is accessible from the top of shield, the

other two are at rear of shield, facing firewall.

2.
Disconnect tachometer drive cables from distributor

housing.

3.
Disconnect pickup coil leads at connector.

4.
Remove distributor cap.

5. Crank engine so rotor is in position to fire No. 1

cylinder and timing mark on harmonic balancer is

indexed with pointer.

6. Remove vacuum line from distributor.

7. Remove distributor clamping screw and hold-down

clamp.

8. Remove distributor and distributor-to-block gasket.

It will be noted that the rotor will rotate as the

distributor is pulled out of the block. Mark the re-

lationship of the rotor and the distributor housing

after removal so that the rotor can be set in the

same position when the distributor is being installed.

DISASSEMBLY (Fig. 16i)

NOTE:
If a distributor is being disassembled

for replacement of the stationary magnetic

pickup assembly only, it will be necessary to

perform only Steps 3, 4, 5, 7, 8, 9, and 12 of the

service procedure listed below.
1.
Remove screws securing rotor and remove rotor.

2.
Remove centrifugal weight springs and weights.

3.
Remove the tachometer drive gear from the distribu-

tor (Corvette only).

4.
Remove roll pin, then remove distributor drive gear

and washer.

CAUTION: To prevent

magnet, support drive gear
;e to the permanent

?n
driving out roll

pin.

5. Remove drive shaft assembly.

6. Remove centrifugal weight support and timer core

from drive shaft.

7. Remove connector from pickup coil leads.

8. Remove retaining ring which secures magnetic

core support plate to distributor shaft bushing in

housing.

9. As a unit, remove the entire magnetic pickup assem-

bly from the distributor housing.

10.
Remove brass washer and felt pad.

11.
Remove vacuum advance unit.

12.
To reassemble distributor, perform the above steps

in reverse order.

INSTALLATION (CORVETTE)

1.
Check to see that the engine is at firing position for

No.
1 cylinder (timing mark on harmonic balancer

indexed with pointer).

2.
Position a new distributor-to-block gasket on the

block.

3.
Before installing distributor, index rotor with hous-

ing as noted when distributor was removed. Install

distributor in block so that vacuum diaphragm faces

approximately 45° forward on the right side of the

engine and the rotor points toward contact in cap for

No.
1 cylinder.

4.
Replace distributor clamp leaving screw loose

enough to allow distributor to be turned for timing

adjustment.

5. Install spark plug wires in distributor cap. Place

wire for No. 1 cylinder in tower (marked on old cap

during disassembly) then install remaining wires

clockwise around the cap according to the firing

order (1-8-4-3-6-5-7-2).

6. Attach distributor to coil primary wires.

7. Replace distributor cap.

8. Adjust timing and then fully tighten distributor clamp

screw.

9. Attach vacuum line to distributor.

10.
Connect tachometer drive cables to distributor body.

11.
Replace ignition shields.

DISTRIBUTOR OFF-ENGINE TEST

The distributor's centrifugal and vacuum advance can

be checked in a distributor testing machine or synchro-

scope specially adapted or designed to accommodate this

type distributor. However, since this involves removing

the distributor from the engine, this test may be post-

poned until other system checks have been made. A dwell

reading cannot be obtained on this distributor and it is not

likely that the centrifugal or vacuum advance will be a

cause of trouble.

COIL REPLACEMENT

1.
Disconnect ignition switch and distributor leads from

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE-ELECTRICAL 6Y-28

terminals on eoil. On Corvettes equipped with radio,

remove bolts securing ignition shield over distribu-

tor and coil.

2.
Pull high tension wire from center terminal of coil.

3.
Remove the two coil support mounting bolts or loosen

friction clamp screw and remove coil.

4.
Place new coil in position and install attaching bolts

or tighten clamp screw.

5.
Place high tension lead securely in center terminal

of coil and connect ignition switch and distributor

primary leads to terminals on coil. Replace ignition

shield on Corvettes.

6. Start engine and test coil operation.

IGNITION PULSE AMPLIFIER

DISASSEMBLY

To check the amplifier for defective components, pro-

ceed as follows:

1.
Remove the bottom plate from the amplifier.

2.
To aid in reassembly, note the locations of the lead

connections to the panel board.

3.
Remove the three panel board attaching screws, and

lift the assembly from the housing.

4.
To aid in reassembly, note any identifying markings

on the two transistors and their respective locations

on the panel board and heat sink assembly.

5.
Note the insulators between the transistors.and the

heat sink, and the insulators separating the heat sink

from the panel board.

6. Remove the transistor attaching screws, and sepa-

rate the two transistors and heat sink from the panel

board.

7.
Carefully examine the panel board for evidence of

damage.

MOUNTING

SCREW

RESISTOR R5 jgSfe. / DIODE Dl

TRANSISTOR TR2

(UNDERNEATH)

1H L >©V

[So

To
I
/'%**jt\
\
TRANSISTC>R"""

1 X ^^w^ X \ (UNDERNEATH)

9^ESISTORR^^^H|^^^^^H

^B
RESISTOR
R4
^HPH^^H

WM'
RESISTOR
R3
I^B^^^^I^U

N .6 ®

mm

N%|/MOUNTING

• tr^i^w ^\ vjR SCREW

CAPACITOR
Cl\
pNkj^^A^
\
RESISTOR
Rl

MOUNTING ^55S^^ \ CAPACITOR C3

SCREW I RESISTOR R6 CAPACITOR C2

TRANSISTOR TR3
COMPONENT CHECKS (Figs. \7\ and 18i)

With the two transistors separated from the assembly,

an ohmmeter may be used to check the transistors and

components on the panel board for defects. An ohmmeter

having a 1-1/2 volt cell, which is the type usually found

in service stations, is recommended. The low range

scale on the ohmmeter should be used except where

specified otherwise.

A 25 watt soldering gun is recommended, and a 60% tin

40%
lead solder should be used when re-soldering. Avoid

excessive heat which may damage the panel board. Chip

away any epoxy involved, and apply new epoxy which is

commercially available.

In order to check the panel board assembly, it is

necessary to unsolder at the locations indicated in Fig-

ure 18i the two capacitors C2 and C3. In all of the fol-

lowing checks, connect the ohmmeter as shown and then

reverse the ohmmeter leads to obtain two readings. The

amplifier circuitry is shown in Figure 19i.

1.
Transistors TR1 and TR2: Check each transistor by

referring to Figure 20i. If both readings in Step 1

are zero, the transistor is shorted. If both readings

in Step 2 are zero, the transistor is shorted; and if

both readings are infinite, the transistor is open.

Interpret Step 3 the same as Step 2.

2.
Trigger Transistor TR3:
11
both readings in Step 1

are zero, the transistor is shorted. If both readings

in Step 2 are zero, the transistor is shorted; and if

both readings are infinite, the transistor is open.

Interpret Step 3 the same as Step 2.

3.
Diode Dl: 11 both readings are zero, the diode is

shorted; and if both readings are infinite, the diode

is open.

4.
Capacitor Cl: If both readings are zero, the capaci-

tor is shorted.

5.
Capacitors C2 and C3: Connect the ohmmeter across

CHECKING

RESISTOR Rl

UNSOLDER
I
CHECKING TRIGGER

TRANSISTOR TR3
CHECKING

CAPACITOR C

Fig.
171—Pulse Amplifier Panel Board
Fig.
18i—Pulse
Amplifier
Component
Checks

CHEVROLET CHASSIS SERVICE MANUAL

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