1967 CHEVROLET CAMARO oil pressure

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
7-23

Assembly (Fig.
4X)

1.
With detent spring tang projecting
up
over
the 3rd

and
4th
shifter shaft cover opening install
the
first

and second detent
cam
onto
the
detent
cam
pivot
pin.

With
the
detent spring tang projecting
up
over
the

first
and
second shifter shaft cover hole install
the

3rd
and 4th
detent
cam,

NOTE:
The 1-2
detent
cam has a
.090" greater

contour
on the
inside detent notch.

2.

3.
Install detent
cam
retaining
"C"
ring
to
pivot shaft,

and hook spring into detent
cam
notches.

Install
1-2 and 3-4
shifter shaft assemblies
in
cover

being careful
not to
damage seals. Install both shift

forks
to
shifter shaft assemblies, lifting
up on
detent
cam
to
allow forks
to
fully seat into position.

4.
Install reverse detent ball
and
spring
to
cover, then

install reverse shifter shaft assembly
to
cover.

5.
Install outer shifter levers, flat washers, lock wash-

ers
and
bolts.

Installation

1.
Shift shifter levers into neutral detent (center) posi-

tion. Position cover gasket
on
case.

2.
Carefully position side cover into place making sure

the shift forks
are
aligned with their respective

mainshaft clutch sliding sleeves.

Install cover attaching bolts
and
tighten evenly
to

specified torque.

Remove filler plug
and add
lubricant specified
in

Section
0, to
level
of
filler plug hole.
3.

4.

ALUMINUM POWERGLIDE

INDEX

Page

General
Description
7-23

Maintenance
and
Adjustments .............. 7—23

Oil
Level Check
7-23

Periodic
Oil
Change
7-24

Periodic
Low
Band Adjustment
7-24

Manual
Shift Linkage Check
and
Adjust
7-24

Floor
Shift Linkage
7-25

Floor
Mounted Control Lever
and

Bracket
Assembly
7-29

Throttle
Valve Linkage
.... 7-29

Neutral
Safety Switch
.. . 7-30

Throttle
Return Check Valve (Dashpot)
7-30

Component
Parts Replacement
7-30

Transmission
Replacement .............. 7—30
Page

Other
Service Operations
7-32

Diagnosis
7-32

Warming
Up
Transmission
7-32

Shop
Warm
Up , 7-32

Road
Warm
Up 7-32

Checking
Fluid Level
and
Condition
7-32

Manual
Linkage
7-32

Oil
Leaks
7-33

Basic
Pressure Checks
7-33

Wide
Open Throttle Upshift Pressure Check
.... 7-33

Idle
Pressure
in
Drive Range
7-33

Manual
"Low"
Range Pressure Check .......
7-33

Drive
Range Overrun (Coast) Pressure
.
.......
7-33

Powerglide
Shift Points
. . 7-35

GENERAL DESCRIPTION

The case
and
converter housing
of the two
speed alumi-

num Powerglide Transmission
is a
single case aluminum

unit. When
the
manual control
is
placed
in the
drive
po-

sition,
the
transmission automatically shifts
to low
gear

for initial vehicle movement.
As the car
gains speed
and

depending
on
load
and
throttle position,
an
automatic shift

is made
to
high gear.
A
forced downshift feature
pro-

vides
a
passing gear
by
returning
the
transmission
to low

range.

The
oil
pump assembly
is a
conventional gear type
and

the
oil
pump housing
is of the
large diameter type acting

as
the
front bulkhead
of the
transmission.
The
torque

converter
is a
conventional three element welded design

bolted
to the
engine flywheel which drives through
a
two-

speed planetary gearset.
The
high clutch assembly
is

typical
of the
designs used
in
this type transmission.
The

aluminum Powerglide uses
an
output shaft mounted
gov-
ernor which requires
a
hole through
the
output shaft.
The

reverse clutch assembly
is a
multiple disc type clutch.

The steel plates
are
splined directly
to the
case while
the

face plates
are
splined
to the
internal
or
ring gear.
The

clutch piston operates within
the
rear portion
of the
case.

The internal diameter
of the
pistoh
is
sealed to
an
integral

hub portion
of the
case rear bulkhead.
The
outside
dia-

meter
is
sealed
to a
machined portion
of the
case.
The

piston
is
hydraulically applied
and is
released
by
separate

coil springs.
The
valve body assembly
is
bolted
to the

bottom
of the
transmission case
and is
accessible
for

service
by
removing
the oil pan
assembly.
The
valve

body consists
of an
upper
and
lower body located
on
either

side
of a
transfer plate.
The
vacuum modulator
is lo-

cated
on the
left rear face
of the
transmission case.
The

modulator valve bore
is
located
in the
upper valve body.

MAINTENANCE
AND
ADJUSTMENTS

OIL LEVEL CHECK

The transmission
oil
level should
be
checked period-

ically
as
recommended
in
Section
0. Oil
should
be
added

only when level
is on or
below
the
"ADD" mark
on the dip

stick with
oil hot or at
operating temperature.
The oil

level
dip
stick
is
located
at the
right rear
of the
engine
compartment. Fill with
oil
specified
in
Section
0.

In order
to
check
oil
level accurately,
the
engine should

be idled with
the
transmission
oil hot and the
control

lever
in
neutral (N) position.

It
is
important that
the oil
level
be
maintained
no

higher than
the
"FULL" mark
on the
transmission
oil

level gauge.
DO NOT
OVERFILL,
for
when
the oil
level

CHEVROLET CHASSIS SERVICE MANUAL

CLUTCH AND TRANSMISSIONS 7-24

is at the full mark on the dip stick, it is just slightly be-

low the planetary gear unit. If additional oil is added,

bringing the oil level above the full mark, the planetary

unit will run in the oil, foaming and aerating the oil. This

aerated oil carried through the various oil pressure pas-

sages (low servo, reverse servo, clutch apply, converter,

etc.) may cause malfunction of the transmission assem-

bly, resulting in cavitation noise in the converter and

improper band or clutch application. Overheating may

also occur.

If the transmission is found consistently low on oil, a

thorough inspection should be made to find and correct

all external oil leaks.

PERIODIC OIL CHANGE

The transmission oil should be changed periodically as

recommended in Section 0, and whenever transmission is

to be removed from the vehicle for repairs.

1.
Run engine for one minute in neutral prior to chang-

ing.

2.
Be sure vehicle is level or raise from the rear only.

3.
Remove the oil pan drain plug and allow oil to drain

thoroughly into a pan or can.

Replace drain plug and refill with approximately two

quarts of oil specified in Section 0.

NOTE: To refill the transmission, remove dip

stick from oil filler tube and refill transmission

with oil specified in Section 0 using filler tube

and funnel J-4264. Then, after shifting into all

ranges at idle speed to fill all oil passages, the

engine should be run at 800-1000 rpm with the

transmission in Neutral until the oil warms up,

then add oil as required to raise the fluid level

to the full mark on the dip stick. Refill capacity

is approximately 2 qts.
4.

Fig.
1PG - Adjusting Low Band Using J-21848
PERIODIC LOW BAND ADJUSTMENT (Fig. 1PG)

Low band adjustment should be periodically performed

at 12,000 mile intervals, or sooner, as necessary if op-

erating performance indicates low band slippage.

1.
Raise vehicle and place selector lever in neutral.

2.
Remove protective cap from transmission adjusting

screw.

3.
a. On Corvette Models: Drop left exhaust pipe for

clearance.

b.
On Chevelle Models: To gain clearance between

underbody and transmission, it may be necessary

to remove rear mount bolts from crossmember,

and move transmission slightly toward passenger

side of vehicle. .

4.
Loosen adjusting screw lock nut 1/4 turn and hold in

this position with wrench.

5.
Using Special Tool J-21848 adjust band to 70 in. lbs.

and back off four (4) complete turns for a band which

has been in operation for 6,000 miles or more,.or

three (3) turns for one in use less than 6,000 miles.

CAUTION: Be sure to hold the adjusting screw

lock nut at 1/4 turn loose with a wrench during"

the.adjusting procedure.

6. Tighten the adjusting screw lock nut to specified

torque.

CAUTION: The amount of back-off is not an

approximate figure, it must be exact.

MANUAL SHIFT LINKAGE CHECK & ADJUST

(Column Type)

1.
The shift tube and lever assembly must be free in the

mast jacket. See Section 9 for alignment of steering

column assembly if necessary.

2.
To check for proper shift linkage adjustment, lift

the transmission selector lever towards the steering

wheel. Allow the selector lever to be positioned in

drive (D) by the transmission detent.

NOTE: Do not use the indicator pointer as a

reference to position the selected lever. When

performing linkage adjustment, pointer is ad-

justed last.

3.
Release the selector lever. The lever should be in-

hibited from engaging low range unless the lever is

lifted.

4.
Lift the selector lever towards the steering wheel,

and allow the lever to be positioned in neutral (N) by

the transmission detent.

5.
Release the selector lever. The lever should now

be inhibited from engaging reverse range unless the

lever is lifted.

6. A properly adjusted linkage will prevent the selector

lever from moving beyond both the neutral detent, and

the drive detent unless the lever is lifted to pass

over the mechanical stop in the steering column.

7.
In the event that an adjustment is required, place

the selector lever in drive (D) position as determined

by the transmission detent. See Steps 2 and 3.

8. Loosen the adjustment swivel at the cross-shaft,

and rotate the transmission lever so that it contacts

the drive stop in the steering column.

9. Tighten the swivel and recheck the adjustment. See

2 and 6.

CHEVROLET CHASSIS SERVICE MANUAL

CLUTCH AND TRANSMISSIONS 7-25

Fig.
2PG - Chevrolet Shift Linkage Adjustments

10.

11.
Readjust indicator needle if necessary to agree with

the transmission detent positions. See Section 9.

Readjust neutral safety switch if necessary to pro-

vide the correct relationship to the transmission

detent positions. See Section 12.

CAUTION: Any inaccuracies in the above ad-

justment may result in premature failure of the

transmission due to operation without controls

in full detent. Such operation results in reduced

oil pressure and in turn partial engagement of

the affected clutches. Partial
of the

clutches with sufficient pressure to cause ap-

parent normal operation of the vehicle will

result in failure of the clutches or other in-

ternal parts after only a few miles of operation.

Floor Shift Linkage

Chevrolet Linkage Adjustment (Fig. 6PG)

1.
Loosely assemble Nuts (A) and (B) on Lower Rod (C).

2.
Set Transmission Lever (D) in drive position.
NOTE:
Obtain drive position by moving Trans-

mission Lever counter-clockwise to low detent,

then clockwise one detent position to drive.

3.
Set Control Pawl Lever Rod (E) in Neutral or drive

notch of Detent (F). See View A.

4.
Apply load in direction of Arrow (Y) on Actuating

Lever (G) until pawl Rod comes in contact with

Detent at Contact Point (Z). See View A.

5. Place a 7/64" Spacer (H) between Nut (A) and Swivel

(J),
run Nut (A) until it touches spacer. Remove

Spacer and apply load in the direction on Arrow (X)

until it touches Nut (A). Tighten Nut (B) against

Swivel and lock Swivel between Nuts (A) and (B).

See View B.

Chevelle Linkage Adjustment (Fig. 7PG)

1.
Assemble Nuts (A) and (B) on Lower Rod (C) loosely.

2.
Set Transmission Lever (D) in drive position.

NOTE:
Obrain drive position by moving Trans-

CHEVROLET CHASSIS SERVICE MANUAL

CLUTCH AND TRANSMISSIONS 7-32

21.
Remove transmission output shaft slip yoke and in-

sert a plastic shipping plug in end of extension to

prevent spillage of transmission fluid.

NOTE:
The yoke is removed to avoid tearing

the heat reflecting pad on the underbbdy, when

the transmission is being removed.

22.
Remove bright metal ignition shielding from dis-

tributor area.

23.
Remove the transmission dip stick and tube

assembly.

24.
Disconnect transmission vacuum modulator line at

distributor advance line tee.

25.
Position transmission hoist under transmission and

attach safety chain to transmission.

26.
Remove transmission converter housing-to-engine

attaching foolts and slide transmission rearward.
NOTE:
Observe converter when moving trans-

mission rearward. If converter does not move

with the transmission, pry it free of flywheel

before proceeding.

27.
Install converter retaining strap.

28.
Lower and remove transmission from vehicle by

tilting the front down and to the right while inter-

mittently lowering the transmission to facilitate its

• removal.

29.
Reinstall transmission assembly by performing the

above steps in reverse order.

Bolt Torques

Transmission Case to Flywheel

Housing Bolts 35 ft. lbs.

Converter to Flywheel Bolts. . , . . 35 ft. lbs.

OTHER SERVICE OPERATIONS

Although certain operations, such as oil pan or gasket

replacement, valve body, governor, filler pipe "O" ring,

speedometer drive gear, case extension "0" ring and

rear oil seal, vacuum modulator, and servo cover or

gasket service may be performed from underneath the
vehicle without removing the Powerglide; their service

procedure is covered in the Passenger Overhaul Manual

and is not repeated here. Refer to the- Powerglide Sec-

tion of the Passenger Overhaul Manual for all other

service operations not covered here.

DIAGNOSIS

Proper operation of the Powerglide transmission may

be affected by a number of factors, all of which must be

considered when trouble in the unit is diagnosed.

Proper trouble diagnosis can only be accomplished

when performed in a thorough step by step procedure.

The following procedure has been devised and tested and

is recommended for all trouble diagnosis complaints and

if the service man will follow this checking procedure,

accurate and dependable diagnosis may be accomplished.

This will result in a savings of time, not only to the

service man, but to the customer as well.

WARMING UP TRANSMISSION

Before attempting to check and/or correct any com-

plaints on the Powerglide transmission it is absolutely

essential that the oil level be checked and corrected if

necessary. An oil level which is either too high or too

low can be the cause of a number of abnormal conditions

from excessive noise to slippage in all ranges.

It must be remembered that cold oil will slow up the

action of the hydraulic controls in the transmission. For

this reason a trouble or oil leak diagnosis should not be

attempted until the transmission has been warmed up by

either of the following procedures:

Shop Warm Up

1.
Connect tachometer to engine.

2.
Set parking brake tight and start engine.

3.
Place selector light in
"D"
(drive) range.

4.
Adjust carburetor idle speed adjusting screw to run

engine at approximately 750 rpm and operate in this

manner for two minutes. At the end of two minutes

of operation, the transmission will be sufficiently

warmed up for diagnosis purposes.
NOTE:
At this point, readjust the engine idle

speed to 450-475 rpm in
"D"
range.

Road Warm Up

Drive the car approximately 5 miles with frequent

starts and stops.

NOTE:
At this point, make sure the engine idle

speed is set to 450-475 rpm in
"D"
range.

CHECKING FLUID LEVEL AND CONDITION

After transmission has been warmed up, check the

fluid level with the engine idling, parking brake set and

control lever in "N" (neutral). If the fluid level is low,

add fluid to bring level up to the full mark on gauge rod,

CAUTION: If fluid level is too high, fluid may

be aerated by the planet carrier. Aerated fluid

will cause turbulence in the converter which will

result in lost power, lower stall speed and lower

pressures in control circuits. Lower fluid level

to full mark, then shut off engine to allow air

bubbles to work out of fluid.

When checking oil level, aburned smell and discolora-

tion indicate burned clutches or bands and the transmis-

sion will have to be removed.

MANUAL LINKAGE

Manual linkage adjustment and the associated neutral

safety switch are important from a safety standpoint.

The neutral safety switch should be adjusted so that the

engine will start in the Park and Neutral positions only.

With the selector lever in the Park position, the park-

ing pawl should freely engage and prevent the vehicle

CHEVROLET CHASSIS SERVICE MANUAL

CLUTCH AND TRANSMISSIONS 7-33

from rolling. The pointer on the indicator quadrant

should line up properly with the range indicators in all

ranges.

OIL LEAKS

Before attempting to correct an oil leak, the actual

source of the leak must be determined. In many cases

the source of the leak can be deceiving due to "wind flow1 f

around the engine and transmission.

The suspected area should be wiped clean of all oil

before inspecting for the source of the leak. Red dye is

used in the transmission oil at the assembly plant and

will indicate if the oil leak is from the transmission.

The use of a "black light"* to identify the oil at the

source of leak is also helpful. Comparing the oil from

the leak to that on the engine or transmission dip stick

(when viewed by black light) will determine the source

of the leak.

Oil leaks around the engine and transmission are gen-

erally carried toward the rear of the car by the air

stream. For example, a transmission "oil filter tube

to case leak" will sometimes appear as a leak at the

rear of the transmission. In determining the source of

an oil leak it is most helpful to keep the engine running.

The mating surfaces of servo cover, converter housing,

transmission case and transmission case extension

should be carefully examined for signs of leakage. The

vacuum modulator must also be checked to insure that

the diaphragm has not ruptured as this would allow trans-

mission oil to be drawn into the intake manifold. Us-

ually, the exhaust will be excessively smoky if the

diaphragm ruptures due to the transmission oil added to

the combustion. The transmission case extension rear

oil seal should also be checked. All test plugs should be

checked to make sure that they are tight and that there

is no sign of leakage at these points. The converter

underpan should also be removed. Any appreciable quan-

tity of oil in this area would indicate leakage at the pump

square seal ring, pump seal assembly, or pump bolt

sealing washers.

BASIC PRESSURE CHECKS

Four basic pressure checks are used for diagnosis and

operational checks for the Aluminum Powerglide trans-

mission. All checks should be made only after thoroughly

warming up the transmission.

• Wide Open Throttle Upshift Pressure.

• Idle Pressure in "Drive" Range.

• Manual "Low" Range Pressure.

• "Drive" Range Overrun (Coast) Pressure.

It is not recommended that stall tests be conducted

which would result in engine vacuum falling below 10" Hg.

Pressure gauge hose connections should be made at

the low servo apply (main line) test point (fig. 14PG).

Run the gauge line into the driving compartment by

pushing aside the mast jacket seal. The line out of the

way of the drivers feet and connect to pressure gauge

J-21867.

• Wide Open Throttle Upshift Pressure Check

Refer to the pressure check chart for upshift pressure
SERVO APPLY

PRESSURE

Fig.
14PG - Pressure Test Plug

points as indicated on the lower servo apply (main line)

gauge.

• Idle Pressure in "Drive" Range

In addition tp the oil pressure gauges, a vacuum gauge

is needed for this check.

With the parking brake applied and the shift selector

lever in "Drive", low servo apply (main line) pressure

should be as shown on the pressure check chart.

If pressures are not within these ranges, the following

items should be checked for oil circuit leakage:

1.
Pressure regulator valve stuck.

2.
Vacuum modulator valve stuck.

3.
Hydraulic modulator valve stuck.

4.
Leak at low servo piston ring (between ring and

bore).

5.
Leak at low servo piston rod (between rod and bore).

6. Leak at valve body to case gasket.

7.
Leak at valve body gaskets.

8. Front pump clearances.

9. Check passages in transmission case for porosity.

• Manual "Low" Range Pressure Check

Connect a tachometer, apply the parking brake, place

the selector lever in "Low" range, and adjust the engine

speed to 1000 rpm with the car stationary.

Low servo apply (main line) pressure should be as

shown on the pressure check chart.

Pressures not within this range can indicate the fol-

lowing possibilities:

1.
Partially plugged oil suction screen.

2.
Broken or damaged ring low servo.

CHEVROLET CHASSIS SERVICE MANUAL

CLUTCH AND TRANSMISSIONS 7-36

TURBO HYDRA-MATIC TRANSMISSION

INDEX

Page

General Description . . , . 7-36

Maintenance and Adjustments . 7-37

Transmission Fluid 7-37

Fluid Level Indicator 7-37

Shift Control Linkage Adjustment ........... 7-37

Neutral Safety Switch Adjustment 7-37

Draining and Refilling Transmission . . . 7-37

Pressure Regulator Valve 7-38

Control Valve Body . 7-39

Governor ..'.... 7-40

Modulator and Modulator Valve 7-40

Parking Linkage . . 7-40
Page

Rear Seal -. 7-40

Other Service Operations . . 7-40

Transmission Replacement 7-40

Turbo Hydra-Matic Diagnosis Procedure. ......... 7-41

Sequence . ; ; 7-41

Oil Level and Condition Check 7-41

Manual Linkage 7-41

Oil Leaks .' 7-41

Case Porosity - Repair ................ 7-42

Oil Pressure Check 7-42

Transmission Shift Points 7-42

Special Tools 7-43

GENERAL DESCRIPTION

The Turbo Hydra-Matic transmission is a fully auto-

matic unit consisting primarily of a 3-element hydraulic

torque converter and a compound planetary gear set.

Three multiple-disc clutches, one sprag unit, one roller

clutch and two bands provide the friction elements re-

quired to obtain the desired function of the compound

planetary gear set.

The torque converter couples the engine to the plane-

tary gears through oil and provides hydraulic torque

multiplication when required. The compound planetary

gear set produces three forward speeds and reverse.

The
3-
element torque converter consists of a pump or

driving member, a turbine or driven member, and a

stator assembly. The stator is mounted on a one-way

roller clutch which will allow the stator to turn clock-

wise but not counter-clockwise.

The torque converter housing is filled with oil and

is attached to the engine crankshaft by a flex plate and

always rotates at engine speed. The converter pump is

an integral part of the converter housing, therefore the

pump blades, rotating at engine speed, set the oil within

the converter into motion and direct it to the turbine,

causing the turbine to rotate.

As the oil passes through the turbine it is traveling in

such a direction that if it were not re-directed by the

stator it would hit the rear of the converter pump blades

and impede its pumping action. So at low turbine speeds,

the oil is re-directed by the stator to the converter pump

in such a manner that it actually assists the converter

pump to deliver power or multiply engine torque.

As turbine speed increases, the direction of the oil

leaving the turbine changes and flows against the rear

side of the stator vanes in a clockwise direction. Since

the stator is now impeding the smooth flow of oil, its

roller clutch releases and it revolves freely on its shaft.

Once the stator becomes inactive, there is no further

multiplication of engine torque within the converter. At

this point, the converter is merely acting as a fluid

coupling as both the converter pump and turbine are

being driven at approximately the same speed - or at a

one-to-one ratio.

A hydraulic system pressurized by a gear type pump

provides the working pressure required to operate the

friction elements and automatic controls.

External control connections to transmission are:
Manual Linkage

Engine Vacuum

12 Volt Electrical

Signal
To select the desired op-

erating range.

To operate a vacuum mod-

ulator unit.

To operate an electrical

detent solenoid.

A vacuum modulator is used to automatically sense

any change in the torque input to the transmission. The

vacuum, modulator transmits this signal to the pressure

regulator for line pressure control, to the 1-2 accumula-

tor valve, and to the shift valves so that all torque re-

quirements of the transmission are met and smooth

shifts are obtained at all throttle openings.

The detent solenoid is activated by an alectric switch

on the carburetor. When the throttle is fully opened, the

switch on the carburetor is closed, activating the detent

solenoid and. causing the transmission to downshift at

speeds below approximately 70 MPH.

The selector quadrant has six selector positions: P,R,

N,D,
L2,L1.

P.
*
- Park position positively locks the output shaft to

the transmission case by means of a locking pawl

to prevent the vehicle from rolling in either di-

rection. The engine may be started in Park

position.

R. - Reverse enables the vehicle to be operated in a

reverse direction.

N.
- Neutral position enables the engine to be started

and run without driving the vehicle.

D,
- Drive Range is used for all normal driving condi-

tions and maximum economy. Drive Range has

three gear ratios, from the starting ratio to

direct drive. Detent downshifts are available by

depressing the accelerator to the floor.

L2.
- L2 Range has the same starting ratio as Drive

Range, but prevents the transmission from shift-

ing above second speed to retain second speed

acceleration when extra performance is desired.

L2 Range can also be used for engine braking.

L2 Range can be selected at any vehicle speed,

and the transmission will shift to second gear and

remain in second until the vehicle speed or the

throttle are changed to obtain first gear operation

in the same manner as in D Range.

CHIVROLET CHASSIS SERVICE MANUAL

CLUTCH AND TRANSMISSIONS 7-41

CAUTION: Use converter holding ToolJ-5384

when lowering transmission or keep rear of

transmission lower than front so as not to lose
converter.

The installation of the transmission is the reverse of

the removal.

TURBO HYDRA-MATIC DIAGNOSIS PROCEDURE

Accurate diagnosis of transmission problems begins

with a thorough understanding of normal transmission

operation. In particular, knowing which units are in-

volved in the various speeds or shifts so that the specific

units or circuits involved in the problem can be isolated

and investigated further. Analytical diagnosis will pro-

tect the technician from come backs and certainly will

improve owner satisfaction.

An important and often overlooked aspect of diagnosis

is finding out specifically what the customer is com-

plaining of. For this purpose a short ride with the cus-

tomer will often prove beneficial. It may be found that

the condition the customer wants corrected is standard

and should not be altered.

The following sequence, based on field experience, pro-

vides the desired information quickly and in most cases

actually corrects the malfunction without requiring the

removal of the transmission. Details of the items listed

in this sequence are covered further in the text.

SEQUENCE FOR TURBO HYDRA-MATIC

DIAGNOSIS PROCEDURE

1.
Check oil level and condition.

2.
Check and correct detent switch.

3.
Check and correct vacuum line and fittings.

4.
Check and correct manual linkage.

OIL LEVEL AND CONDITION CHECK

Always check the oil level before road testing. Oil

must be visible on dip stick prior to operating the ve-

hicle. Erratic shifting, pump noise, or other malfunc-

tions can in some cases be traced to improper oil level.

Oil level should be checked with the selector lever in

the Park (P) position, engine running, and the vehicle on

level pavement.

Fluid level should be to the FULL mark with the trans-

mission at normal operating temperature (170°-190°
F.).

With warm fluid (room temperature), the level should be

at or slightly below the ADD mark.

If oil level was low, refer to Oil Leaks.

The condition of the oil is often an indication of whether

the transmission should be removed from the vehicle, or

to make further tests. When checking oil level, a burned

smell and discoloration indicate burned clutches or bands

and the transmission will have to be removed.

MANUAL LINKAGE

Manual linkage adjustment and the associated neutral

safety switch are important from a safety standpoint

The neutral safety switch should be adjusted so that the

engine will start in the Park and Neutral positions only.

With the selector lever in the Park position, the park-

ing pawl should freely engage and prevent the vehicle

from rolling. The pointer on the indicator quadrant

should line up properly with the range indicators in all

ranges.
OIL LEAKS

Before attempting to correct an oil leak, the actual

source of the leak must be determined. In many cases,

the source of the leak can be deceiving due to "wind flow"

around the engine and transmission.

The suspected area should be wiped clean of all oil be-

fore inspecting for the source of the leak. Red dye is

used in the transmission oil at the assembly plant and

will indicate if the oil leak is from the transmission.

. The use of a "black light"* to identify the oil at the

source of leak is also helpful. Comparing the oil from

the leak to that on the engine or transmission dip stick

(when viewed by black light) will determine the source

of the leak.

Oil leaks around the engine and transmission are gen-

erally carried toward the rear of the car by the air

stream. For example, a transmission "oil filler tube to

case leak" will sometimes appear as a leak at the rear of

the transmission. In determining the source of an oil

leak it is most helpful to keep the engine running.

POSSIBLE POINTS OF OIL LEAKS

• 1. TRANSMISSION OIL PAN LEAK

a. Attaching bolts not correctly torqued.

b.
Improperly installed or damaged pan gasket.

c. Oil pan gasket mounting face not flat.

2.
REAR EXTENSION LEAK

a. Attaching bolts not correctly torqued.

b.
Rear seal assembly — damaged or improperly

installed.

c. Gasket seal — (extension to case) damaged or

improperly installed.

d. Porous casting.

3.
CASE LEAK

a. Filler pipe "O" ring seal damaged or missing;

misposition of filler pipe bracket to engine —

"loading" one side of
"O"
ring.

b.
Modulator assembly "O" ring seal
—
damaged or

improperly installed.

c. Governor cover, gasket and bolts — damaged,

loose; case face leak.

d. Speedo gear
—
"O" ring damaged.

e. Manual shaft seal — damaged, improperly in-

stalled.

f. line pressure tap plug — stripped, shy sealer

compound.

g. Parking pawl shaft cup plug
—
damaged, improp-

erly installed.

h. Vent pipe (refer to Item 5).

i. Porous case.

4.
FRONT END LEAK

a. Front seal - damaged (check converter neck for

nicks,
etc., also for pump bushing moved for-

ward);
garter spring missing from pump to con-

verter seaL

b.
Pump attaching bolts and seals
—
damaged, miss-

ing, bolts loose.

CHEVROLET a
SERVICE