
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-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-31
CAUTION: Before adjusting gap, me center
INSTALLATION
electrode flat. In adjusting the spark pluig Install the spark plugs in the engine with new gaskets
gap,
never bend the center electrode which and tighten to specifications. If torque wrench is not
extends through the porcelain center. Always available, tighten plugs finger tight and 1/2 turn more.
make adjustment by bending the ground or , Plugs are of a 14 millimeter size and care must be
side electrode. exercised when installing or the gap setting may be
changed.
CHEVROLET CHASSIS SERVICE MANUAL

SECTION 7
CLUTCH AND TRANSMISSIONS
CONTENTS OF THIS SECTION
Clutch
Three-Speed . . .
Overdrive
Three-Speed, (Warner T-16)
Four-Speed (Muncie) . . . .
Page
7-1
7-6
7-9
7-14
7-16
CLUTCH
Page
Four-Speed (Saginaw) 7-20
Powerglide 7-23
Turbo Hydra-Matic 7-36
Special Tools 7-43
INDEX
General Description
Maintenance and Adjustments
Linkage Inspection
Clutch Linkage Adjustment
Component Parts Replacement
Clutch Assembly ......
Removal from Vehicle .
Page
7-1
7-1
7-1
7-2
7-3
7-3
7-3
Installation in Vehicle
Clutch Pedal ..'....,
Clutch Cross Shaft . . .
Removal.......
Repairs
Installation .....
Page
7-4
7-4
7-4
7-4
7-4
7-4
GENERAL DESCRIPTION
A diaphragm spring-type clutch assembly is used with
manual transmissions.
The clutch assembly is enclosed in a 360° bell housing
which must be removed to gain access to the clutch.
V-8 engines (equipped with a 4 speed transmission)
use a bent-finger, centrifugal diaphragm type clutch as-
sembly. All its integral release fingers are bent back to
gain a centrifugal boost and to insure quick re engagement
at high engine speeds.
This type of clutch has the advantages of increasing
pressure plate load as the driven plate wears, and of low
pedal effort with high plate loads without requiring over-
center booster springs on the clutch linkage.
The pressure plate is a high tensile strength iron de-
signed for maximum speed conditions.
The clutch release bearing (fig. 4), used with the bent
finger diaphragm clutch, has an overall length of approxi-
mately
1-1/4".
The longer bearing, used with the straight
diaphragm, will cause inability to obtain free pedal travel,
especially as the clutch wears, resulting in slippage and
rapid wear.
DO
NOT INTERCHANGE!
The clutch is operated by conventional linkage consist-
ing of two groups, upper linkage and lower linkage.
The return spring pre-loads clutch linkage, removing
looseness due to wear. The clutch free pedal travel,
therefore, will increase with linkage wear and decrease
with driven disc wear, and free travel felt at pedal is
throwout bearing lash.
MAINTENANCE AND ADJUSTMENTS
LINKAGE INSPECTION
There are several things which affect good clutch op-
eration. Therefore, it is necessary, before performing
any major clutch operations, to make preliminary in-
spections to determine whether trouble is actually in the
clutch.
Check the clutch linkage to be sure the clutch releases
fully as follows:
1.
With engine running, hold the clutch pedal approxi-
mately 1/2" from floor mat and move shift lever be-
tween first and reverse several times. If this can be
done smoothly, the clutch is fully releasing. If shift
is not smooth, clutch is not fully releasing and ad-
justment is necessary.
2.
Check clutch pedal bushings for sticking or excessive
wear.
3.
Check fork for proper installation on ball stud. Lack
of lubrication on fork can cause fork to be pulled off
the ball.
4.
Check for bent, cracked or damaged cross shaft
levers or support bracket.
5.
Loose or damaged engine mounts may aUiow the en-
gine to shift its position causing a bind on clutch
linkage at the cross shaft. Check to be sure there is
Fig.
1 - Chevrolet Clutch Pedal Free Travel Adjustment
CHEVROLET CHASSIS SERVICE MANUAL

CLUTCH AND TRANSMISSIONS 7-2
Fig.
2 - Chevelle Clutch Pedal Free Travel Adjustment (V-8 Shown)
some clearance between cross shaft and both its
mounting brackets.
CLUTCH LINKAGE ADJUSTMENT
There is one linkage adjustment (clutch fork push rod
or pedal push rod) to compensate for all normal clutch
wear.
The clutch pedal should have
1-1/4"
free travel (meas-
ured at clutch pedal pad) before the throwout bearing en-
gages the clutch diaphragm spring levers. Lash is re-
quired to prevent clutch slippage which would occur if the
bearing was held against the fingers and to prevent the
bearing from running continually until failure.
Chevrolet Linkage Adjustment (Fig. 1}
With Nuts (A) & (B) loose on Rod (D)
&
before installa-
tion of Clutch Pedal Return Spring
(E),
apply approximately
5 lbs. load in direction of arrow (F) to eliminate clear-
ance between throwout bearing and clutch fingers. Move
Rod (D) in direction of arrow (G) until Clutch Pedal Arm
makes contact with Bumper Stop on instrument panel
brace. Run Nut (B) toward Swivel until dimension (X) is
9/32". Tighten Nut (A) to lock Swivel (C) against Nut (B).
Install Clutch Pedal Return Spring (E).
The foregoing procedure will provide a free pedal
travel of 1" to
1-1/2"
measured on a perpendicular from
the crown of the, pedal pad to the bare metal toe pan.
Chevelle Linkage Adjustment (Fig. 2)
1.
Disconnect spring between cross shaft lever and
clutch fork.
2.
Loosen push rod locknut about three turns.
3.
If there is no free travel, shorten the rod (by turning
at square wrench area) until it is free of clutch fork.
4.
Hold the clutch fork rearward to move throwout
lightly against clutch release fingers, then adjust rod
length until rod just touches ,its seat in the fork.
5.
Adjust locknut to obtain approximately 3/16" clear-
ance between nut and rod sleeve end.
6. Turn the rod with wrench, until the nut just comes in
contact with rod sleeve end, then hold the rod with
wrench and tighten locknut.
7.
Check free pedal travel at pedal (1" to
1-1/2"
is
proper clearance). Readjust if necessary.
Chevy II Linkage Adjustment (Fig. 3}
L-4 & L-6 Models
1.
Loosen locknut "A" and lengthen or shorten push rod
in swivel as required by turning with wrench on ma-
chined flat "B". (Shorten push rod to increase pedal
lash).
2.
Hold push rod at flat "B" and tighten locknut "A".
3.
Recheck pedal free travel.
NOTE: A measurement of approximately 3/16"
between push rod and its seat in fork will give
required pedal free travel.
V-8 Models
The eight cylinder linkage has a two-piece clutch fork
push rod (fig. 3). Adjust clutch pedal free travel by turn-
ing the adjusting rod portion of the push rod to obtain apr
proximately 3/16" clearance between clutch fork and end
of rod, ttien tighten locknut to 8-12 lbs. ft. and check free
travel at pedal. Pedal free travel on all models should
be 1" to
1-1/2".
Corvette Linkage Adjustment
Refer to fig. 1 and the following procedure:
1.
Disconnect pedal return spring.
2.
With Nuts (A) and (B) loose on Rod (D) apply push
hard load in direction of arrow (F) to eliminate
clearance between throwout bearing and clutch
fingers.
3.
Run Nut (B) towards Swivel (C) until dimension (X)
is 3/8" to 7/16".
4.
Tighten Nut (A) to lock swivel against Nut (B).
5.
Connect pedal return spring and check pedal free
travel for
1-1/4"
minimum to 2" maximum.
6. Check every 3,000 miles.
7.
Adjust free travel to 2" to 2-1/2" for heavy duty op-
eration. The return spring may be removed for
heavy duty conditions.
Camaro Linkage Adjustment
Refer to Figure 4 and the following procedure:
Apply a 10 lb. load in direction of Arrow (E) to hold
Clutch Pedal against Clutch Pedal Bumper.
Apply a 10 lb. load to Clutch Fork in direction of Arrow
(D) to eliminate clearance between throwout bearing and
clutch fingers.
Insert a .198 Spacer (F) between clutch fork and Ad-
justing Rod (A).
Rotate Adjusting Rod against Spacer until it has a 5 in.
lb.
torque.
Hold Adjusting Rod and tighten Nut (C) against Swivel
(B) or Rod (B).
Remove Spacer. Install return spring and extension to
clutch fork.
Pedal will have approximately 1" to
1-1/8"
free travel.
A clutch that has been slipping prior to free play ad-
justment may still slip right after the new adjustment due
CHEVROLET CHASSIS SERVICE MANUAL

CLUTCH AND TRANSMISSIONS 7-3
•BUMPER
CLUTCH FORK
CLUTCH PEDAL
L-4 AND L-6 MODELS
Fig.
3 - Chevy II Clutch Pedal Free Travel Adjustment
to previous heat. The vehicle should be returned to the
Dealership the next day (at least 12 hours) to give clutch
time to cool to normal temperatures. Any slippage
should then be evaluated as follows:
1.
Drive in high gear at 20-25 MPH.
2.
Depress clutch pedal to the floor and rev engine to
2500-3500 rpm.
3.
Engage clutch quickly (snap foot off pedal) and press
accelerator to full throttle.
Engine speed should drop noticeably then accelerate
with vehicle. If clutch is bad, the engine speed will in-
crease.
NOTE: Do not repeat more than once or clutch
, will overheat.
-NUTC NUTC
SPACER F
SPACER F
RODB
' CLUTCH^ SWIVEL B
FORK
ADJUSTING
ROD
A '
V8 ENGINE
ADJUSTING
ROD
A
L6 ENGINE
Fig.
4 - Clutch Pedal Free Travel Adjustment
COMPONENT PARTS REPLACEMENT
CLUTCH ASSEMBLY
Removal From Vehicle
1.
Support engine and remove transmission as outlined
in transmission section.
2.
Disconnect clutch fork push rod and spring.
3.
Remove flywheel housing.
4.
Slide clutch fork from ball stud and remove fork from
dust boot.
NOTE: Ball stud is threaded into clutch hous-
ing and is easily replaced, if necessary.
CHEVROLET CHASSIS SERVICE MANUAL

CLUTCH AND TRANSMISSIONS 7-4
5.
Install Tool J-5824 to support the clutch assembly
during removal.
NOTE: Look for "X" mark on flywheel and on
clutch cover. If MX" mark is not evident, prick
punch marks on flywheel and clutch cover for
indexing purposes during installation.
6. Loosen the clutch-to-flywheel attaching bolts evenly
1 turn at a time until spring pressure is released,
then remove the bolts, and remove clutch assembly.
Installation to Vehicle
Clean pressure plate and flywheel face. (They should
be free of oil, grease, metal deposits or burned spots).
1.
Position the clutch disc and pressure plate in relar
tive installed position and support them with align-
ment Tool J-5824.
NOTE: The driven disc on the 4 and 6 cylinder
engines is installed with the damfper springs to
the flywheel side; the V-8 is opposite, however,
THE GREASE SLINGER IS ALWAYS ON THE
TRANSMISSION SIDE.
2.
Turn clutch assembly until "X" mark on cover lines
up with "X" mark oh flywheel, then align cover bolt
holes to nearest flywheel holes.
3.
Install a bolt in every hole and tighten down evenly
and gradually until tight (to avoid possible clutch
distortion).
NOTE: Cover loads are as high as 1-1/4 tons.
4.
Remove pilot tool.
5.
Unhook clutch fork and lubricate ball socket and fork
fingers at release bearing end with a high melting
point grease such as graphite and reinstall fork on
ball stud. On Corvette models use Moly Grease.
6. Lubricate the recess on the inside of throwout bear-
ing collar and the throwout fork groove with a light
coat of graphite grease (fig. 4). On Corvette models
use Moly Grease.
7.
Install clutch fork and dust boot into clutch housing
and install throwout bearing to the throwout fork, then
install flywheel housing.
8. Install transmission as outlined in transmission
section.
9. Connect fork push rod and spring.
10.
Adjust shift linkage as outlined in transmission
section.
11.
Perform linkage adjustment for pedal free play and
check clutch release position.
CLUTCH PEDAL
The clutch pedal is the pendant-type hung from a sup-
Fig. 5 - Release Bearing Lubrication and Comparison
port brace common to the brake pedal and must be re-
moved to remove brake pedal. Refer to Section 5 for
brake and clutch pedal service procedure.
CLUTCH CROSS SHAFT (Figs. 6, 7 & 8)
Removal
1.
Remove linkage return and lower linkage springs and
disconnect clutch pedal and fork push rods from re-
spective cross shaft levers.
2.
Loosen outboard ball stud nut and slide stud out of
bracket slot.
3.
Move cross shaft outboard, and as required to clear
inboard ball stud, then merely lift out to remove
from vehicle.
Repairs
The cross shaft has nylon ball stud seats which should
be inspected for wear or damage. Also check condition
of engine bracket ball stud assembly and special anti-
rattle "O" ring. Figures 6, .7
&
8 show component parts
of cross shaft. Replace parts as necessary based on wear
or damage. Lubricate ball studs and seats with graphite
grease before reassembly.
Installation
1.
Reverse removal procedure to install.
2.
Adjust clutch linkage as previously outlined.
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