FORD MUSTANG 1969 Volume One Chassis

06-04-02

Specifications

06-04-02

TORQUE LIMITS(FT-LBS)

Extension Housing Bolts

Input Shaft Bearing Retainer-to-Transmission Case Bolts

Speedometer Cable Retainer-to-Transmission Extension

Transmission-to-Flywheel Housing Bolts

Gearshift Control Levers to Cam and Shaft Assembly Lock Nuts

Transmission Cover Bolts

Filler Plug-to-Case

Drain Plug-to-Case

Shift Fork-to-Shift Rail

Third and Fourth Shift Rail Detent Bolt

Gear Shift Control Assembly
to
Transmission Extension

Shift Selector Levers to Shift Rods

Gear Shift Control Support Bracket
to
Back Plate
3-Speed

Transmissions

42-50

30-36

3.0-4.5

37-42

18-23

14-19

10-20

20-30

10-18

-

8-12

10-20

-
4-Speed

Transmissions

42-50

19-25

3.0-4.5

37-42

18-23

14-19

10-20

20-30

10-18

10-18

8-12

10-20

8-13
® Inch-pounds

SPECIAL TOOLS
SPECIAL TOOLS (Continued)

Tool Numbers

T50T-100A

T59L-100B

Tool-1175AB

T53T-4621-Bor(4621-F)

T57L-4220-A4

T52L-7000-GAE

T63P-7025-A

T64P-7025-B

T53T-4621-C
Description

Impact Hammer-Long

Impact Hammer-Short

Grease Seal Remover

Drive Pinion Bearing Cone

Replacer Front
&
Rear

Differential Side Bearing Cone

Replacer
or
Input Shaft Bearing

Remover

Extension Housing Bushing and

Seal Remover

Output Shaft Bearing Remover

& Replacer

Output Shaft Bearing Remover

& Replacer

Drive Pinion Bearing

Cone Replacer
Tool Numbers

Tool-7025-B

Tool-7025-G

T64P-7111-A

T63P-7111-A

T64P-7140-A

T61L-7657-A

T57P-7697-B

T57P-7657-G

T67P-7341-A
Description

Rear Main Shaft Bearing Removei

Main Shaft Bearing Remover

& Replacer

Cluster Gear Roller Retainer Shaf

Cluster Gear Roller Retainer Shaft

Reverse Idler Shaft Remover

Transmission Extension Housing

Oil Seal Replacer

Extension Housing

Bushing Replacer

Extension Housing

Bushing Replacer

Shift Linkage Grommet

Replacerprocarmanuals.com

07-01-01

07-01-01

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'y.y... -4^*:
GROUP

7

PART
7-1
PAGE

General Transmission Service
07-01-01

PART
7-2

C4 Automatic Transmission
07-02-01

PART
7-3

FMX Transmission
07-03-01
PART
7-4

C6 Automatic Transmission
....

PART
7-5

Specifications
PAGE

07-04-01

07-05-01

TRANSMISSION

CODE
TRANSMISSION

TYPE

AUTOMATIC
(C4)

U AUTOMATIC
(C6)

X AUTOMATIC
(FMX)

Z AUTOMATIC
(C6
SPECIAL)

D2040-A

FIG. 1—Typical Warranty Plate—Transmission Identification

PART
7-1
General
Transmission
Service

COMPONENT INDEX

AIR PRESSURE CHECKS

ANTI-STALL DASHPOT CLEARANCE

CHECK

(Engine Compartment)

CASE (Transmission)

Inspection

CONTROL PRESSURE CHECK

CONTROL VALVE BODY

Inspection

CONVERTER

Checking

Cleaning

DRAIN AND REFILL (Transmission)

ENGINE IDLE SPEED CHECK

EXTENSION HOUSING INSPECTION

FLUID AERATION CHECK
MODEL APPLICATION
All
Models

01-06

01-04

01-17

01-05

01-17

01-04

01-11

01-08

01-04

01-15

01-03
Ford
Mercury
Meteor
Cougar
Fairiane
Falcon
Montego
Mustang
Lincoln-
Continental
Thunderbird
Continental-
Mark
III

A page number indicates that the item
is for
the vehicle listed
at
the head
of
the column.

N/A indicates that the item
is not
applicable
to
the vehicle listed.
procarmanuals.com

07-01-02

General Transmission Service

07-01-02

COMPONENT INDEX

FLUID LEAKAGE CHECK

FLUID LEVEL CHECK

FRONT CLUTCH (Forward) INSPECTION

C4 Transmission

C6 Transmission

FMX Transmission

FRONT PUMP AND STATOR SUPPORT

Inspection

FRONT SERVO (Intermediate) INSPECTION

C4 Transmission

C6 Transmission

FMX Transmission

GOVERNOR INSPECTION

HYDRAULIC SYSTEM BENCH TESTS

(FMX)

Pressure Tests

Testing Tool Installation

MANUAL LINKAGE CHECKS

MANUAL SHIFT LINKAGE GROMMET

COLUMN SHIFT

Removal and Installation

NEUTRAL START SWITCH-COLUMN

SHIFT

Adjustment

Removal and Installation

OIL COOLER CLEANING

OIL COOLER TUBES

Removal and Installation

ONE-WAY CLUTCH INSPECTION

OUTPUT SHAFT AND PRIMARY SUN

GEAR

Shaft (FMX)

Inspection

PINION CARRIER, ONE-WAY CLUTCH

AND CENTER SUPPORT (FMX)

Inspection

PINION CARRIERS INSPECTION

C4 Transmission

C6 Transmission

PRESSURE REGULATOR (FMX)

Inspection

REAR CLUTCH (Reverse-High) INSPECTION

C4 Transmission

C6 Transmission

FMX Transmission

REAR SERVO (Low-Reverse) INSPECTION

C4 Transmission
MODEL APPLICATION
All
Models

01-03

01-03

01-16

01-17

01-04

01-11

01-08

01-17
Ford
01-16

01-16

01-16

01-17

01-17

01-17

01-08

01-07

01-11

01-09

01-10

01-12

01-15

01-15

01-15

01-17

01-16

01-16

01-16

01-17

01-17
Mercury
N/A

01-16

N/A

N/A

01-17

N/A

N/A

N/A

01-11

01-09

01-10

N/A

N/A

N/A

01-15

N/A

N/A

01-16

N/A

N/A

N/A
Meteor
01-16

01-16

01-16

01-17

01-17

01-17

01-08

01-07

01-11

01-09

01-10

01-12

01-15

01-15

01-15

01-17

01-16

01-16

01-16

01-17

01-17
Cougar
N/A

01-16

01-16

N/A

01-17

01-17

01-08

01-07

N/A

N/A

N/A

01-12

01-15

N/A

01-15

01-17

N/A

01-16

01-16

N/A

01-17
Fairlane
01-16

01-16

01-16

01-17

01-17

01-17

01-08

01-07

01-11

01-09

01-10

01-12

01-15

01-15

01-15

01-17

01-16

01-16

01-16

01-17

01-17
Falcon
01-16

N/A

N/A

01-17

N/A

N/A

N/A

N/A

01-11

01-09

01-10

N/A

N/A

01-15

N/A

N/A

01-16

N/A

N/A

01-17

N/A
Montego
01-16

01-16

01-16

01-17

01-17

01-17

01-08

01-07

01-11

01-09

01-10

01-12

01-15

01-15

01-15

01-17

01-16

01-16

01-16

01-17

01-17
Mustang
01-16

01-16

01-16

01-17

01-17

01-17

01-08

01-07

N/A

N/A

N/A

01-12

01-15

01-15

01-15

01-17

01-16

01-16

01-16

01-17

01-17
Lincoln-
Continental
N/A

01-16

N/A

N/A

01-17

N/A

N/A

N/A

01-11

01-09

01-10

N/A

N/A

N/A

01-15

N/A

N/A

01-16

N/A

N/A

N/A
Thunderbird
N/A

01-16

N/A

N/A

01-17

N/A

N/A

N/A

01-11

01-09

01-10

N/A

N/A

N/A

01-15

N/A

N/A

01-16

N/A

N/A

N/A
Continental-
Mark
III
N/A

01-16

N/A

N/A

01-17

N/A

N/A

N/A

01-11

01-09

01-10

N/A

N/A

N/A

01-15

N/A

N/A

01-16

N/A

N/A

N/A

A page number indicates that the item is for the vehicle listed at the head of the column.

N/A indicates that the item is not applicable to the vehicle listed.
procarmanuals.com

07-01-03

General Transmission Service

07-01-03

COMPONENT INDEX

FMX Transmission

REAR SUPPORT (FMX)

Inspection

SHIFT POINT CHECKS

STATOR ONE-WAY CLUTCH CHECK

STATOR TO IMPELLOR INTERFERENCE

CHECK

STATOR TO TURBINE INTERFERENCE

CHECK

TRANSMISSION CLEANING

TURBINE AND STATOR END PLAY

CHECK

VACUUM DIAPHRAGM ADJUSTMENT

Altitude Compensating Type

Non-Altitude Compensating Type

VACUUM UNIT CHECK

Altitude Compensating Type

Non-Altitude Compensating Type
MODEL APPLICATION
All
Models

01-06

01-12

01-12

01-12

01-11

01-12
Ford
01-17

01-16

N/A

01-08

N/A

01-05
Mercury
N/A

N/A

N/A

01-08

N/A

01-05
Meteor
01-17

01-16

N/A

01-08

N/A

01-05
Cougar
01-17

01-16

N/A

01-08

N/A

01-05
Fairlane
01-17

01-16

N/A

01-08

N/A

01-05
Falcon
N/A

N/A

N/A

01-08

N/A

01-05
Montego
01-17

01-16

N/A

01-08

N/A

01-05
Mustang
01-17

01-16

N/A

01-08

N/A

01-05
Lincoln-
Continental
N/A

N/A

01-09

N/A

01-06

N/A
Thunderbird
N/A

N/A

01-09

N/A

01-06

N/A
Continental-
Mark
III
N/A

N/A

01-09

N/A

01-06

N/A

A page number indicates that the item is for the vehicle listed at the head of the column.

N/A indicates that the item is not applicable to the vehicle listed.

Three different three-speed trans-

missions are used. The C4 Automatic,

C6 Automatic and the FMX Auto-

matic. Part 7-1 covers testing, com-
mon adjustments and repairs, and

cleaning and inspection for the three

types of transmissions. Where there
are differences in procedures or speci-

fications, the type of transmission af-

fected will be designated.

l
AUTOMATIC TRANSMISSION TESTS

When diagnosing transmission

problems, refer to the Ford Car and

Truck Diagnosis Manual for the de-

tailed information on the items that

could be causing the problem.

The following preliminary checks

should be made before proceeding

with other diagnosis checks.

TRANSMISSION FLUID LEVEL

CHECK

1.
Make sure that the vehicle is

standing level. Then firmly apply the

parking brake.

2.
Run the engine at normal idle

speed. If the transmission fluid is cold

run the engine at fast idle speed

(about 1200 rpm) until the fluid reach-

es its normal operating temperature.

When the fluid is warm, slow the en-

gine down to normal idle speed.

3.
On a vehicle equipped with a

vacuum brake release, disconnect the

release line and plug the end of the
line;
otherwise the parking brake will

not hold the transmission in any drive

position.

4.
Shift the selector lever through

all positions, and place the lever at P.

Do not turn off the engine during the

fluid level checks.

5.
Clean all dirt from the transmis-

sion fluid dipstick cap before remov-

ing the dipstick from the filler tube.

6. Pull the dipstick out of the tube,

wipe it clean, and push it all the way

back into the tube. Be sure it is prop-

erly seated.

7.
Pull the dipstick out of the tube

again, and check the fluid level. The

fluid level should be above the ADD

mark. If necessary, add enough fluid

to the transmission through the filler

tube to bring the level between the

ADD and FULL marks on the dip-

stick. Do not overfill the transmission.

Install the dipstick, making sure it is

fully seated in the tube.
8. Connect the vacuum brake re-

lease line if so equipped, and test it

for proper operation.

FLUID AERATION CHECK

A fluid level that is too high will

cause the fluid to become aerated:

Aerated fluid will cause low control

pressure, and the aerated fluid may be

forced out the vent.

Check the transmission fluid level.

Low fluid level can affect the opera-

tion of the transmission, and may in-

dicate fluid leaks that could cause

transmission damage.

TRANSMISSION FLUID

LEAKAGE CHECKS

Check the speedometer cable con-

nection at the transmission. Replace

the rubber seal if necessary.

Leakage at the oil pan gasket often

can be stopped by tightening the at-
procarmanuals.com

07-01-04
General Transmission Service

07-01-04

taching bolts to the proper torque. If

necessary, replace the gasket.

Check the fluid filler tube connec-

tion at the transmission case or pan.

If leakage is found here, install a new

O-ring or tighten the fitting to the

specified torque.

Check the fluid lines and fittings

between the transmission and the

cooler in the radiator tank for loose-

ness,
wear, or damage. If leakage can-

not be stopped by tightening a fitting,

replace the damaged parts.

Check the engine coolant in the ra-

diator. If transmission fluid is present

in the coolant, the cooler in the radia-

tor is probably leaking.

The cooler can be further checked

for leaks by disconnecting the lines

from the cooler fittings and applying

50-75 psi air pressure to the fittings.

Remove the radiator cap to relieve the

pressure build at the exterior of the oil

cooler tank. If the cooler is leaking

and will not hold this pressure the

cooler must be replaced. Cooler re-

placement is described in the Cooling

System Section of Group 11.

If leakage is found at either the

downshift control lever shaft or the

manual lever shaft, replace either or

both seals.

Inspect the pipe plug on the left

side of the transmission case at the

front. If the plug shows leakage, tor-

que the plug to specifications. If tight-

ening does not stop the leaks, replace

the plug. On a C6 transmission, a TV

pressure plug is also provided on the

right rear side of the case.

When converter drain plugs leak,

remove drain plugs with a six-point

wrench. Coat the threads with FoMo-

Co Perfect Seal Sealing Compound or

its equivalent, and install the plugs.

Torque the drain plugs to specifica-

tion. Fluid leakage from the converter

housing may be caused by engine oil

leaking past the rear main bearing or

from oil gallery plugs, or power steer-

ing oil leakage from steering system.

Be sure to determine the exact cause

of the leak before repair procedures

are started.

Oil-soluble aniline or fluorescent dyes

premixed at the rate of 1/2 teaspoon

of dye powder to 1/2 pint of transmis-

sion fluid have proved helpful in locat-

ing the source of the fluid leakage.

Such dyes may be used to determine

whether an engine oil or transmission

fluid leak is present or if the fluid in

the oil cooler leaks into the engine

coolant system. A black light, how-

ever, must be used with the fluorescent

dye solution.
DISHED OR

FLAT WASHER

" O.D.,
a" STEEL PLATE

5/8"X \W,

DRILL TO SUIT
HEX. HEAD SCREW

3/8"-24 X Vl

HEX. NUT W—
24

WELD

TOGETHER

WING
NUT

>/2"_13
THREAD

CHAIN,
10"
LONG
RUBBER PLUG

1
Vi" DIA. X 2"

LONG Vl"

HOLE THRU

APPROXIMATELY

40 DUROMETER
FLAT WASHER

Vs" O.D.

PLUG

VALVE
STANDARD BOLT

W-13
X 4Vl"

LONG SQUARE

THREAD
END

REMOVE HEAD

AND WELD
TO

WASHER

STANDARD 1/8" FITTING-87971-S FOR

RETAPPED DRAIN PLUG THREADS-USE

1/4" OVERSIZE FITTING-87973-S

D 1067-B
WELD TOGETHER

SECURELY—MUST

NOT LEAK

FIG. 2—Converter Leak Checking Tool

CONVERTER LEAKAGE

CHECK

If there are indications that the

welds on the torque converter are

leaking, the converter will have to be

removed and the following check

made before the unit is replaced.

A leak checking tool (Fig. 2) can be

made from standard parts. The tool

can be used to check all converters.

1.
Install the plug in the converter

(Fig. 3) and expand it by tightening

the wing nut. Attach the safety chains.

2.
Install the air valve in one of the

drain plug holes.

3.
Introduce air pressure into the

converter. Check the pressure with a

tire gauge and adjust it to 20 psi.

4.
Place the converter in a tank of

water. Observe the weld areas for

bubbles. If no bubbles are observed, it

may be assumed that the welds are

not leaking.

ENGINE IDLE SPEED CHECK

Check and, if necessary, adjust the

engine idle speed, using the procedure

given in Group 10.

If the idle speed is too low, the en-

gine will run roughly. An idle speed

that is too high will cause the vehicle

to creep, have harsh engagements and

harsh closed-throttle downshifts.
ANTI-STALL DASHPOT

CLEARANCE CHECK

After the engine idle speed has been

properly adjusted, check the anti-stall

dashpot clearance. Follow the proce-

dure given in Group 10 for checking

and adjusting this clearance.

MANUAL LINKAGE CHECKS

Correct manual linkage adjustment

is necessary to position the manual

valve for proper fluid pressure direc-

tion to the different transmission com-

ponents. Improperly adjusted manual

Tire Pressure Gauge

D1921-A

FIG. 3—Converter Leak Checking

Tool Installationprocarmanuals.com

07-01-05
General Transmission Service

07-01-05

linkage may cause crossleakage and

subsequent transmission failure. Refer

to Linkage Adjustments in Part 7-2,

7-3 or 7-4 for detailed manual linkage

adjustment procedures.

CONTROL PRESSURE

CHECK

When the vacuum diaphragm unit is

operating properly and the downshift

linkage is adjusted properly, all the

transmission shifts (automatic and

kickdown) should occur within the

road speed limits specified in Part 7-5.

If the shifts do not occur within

limits or the transmission slips during

shift point, the following procedure is

suggested to determine engine, trans-

mission, linkage, vacuum diaphragm

unit or valve body problems.

1.
Using the automatic transmis-

sion tester (Fig. 4), attach the tachom-

eter to the engine and the vacuum

gauge to the transmission vacuum line

at the vacuum unit (Fig. 5).

D 1823-A

. 4—Rotunda ARE-2905

Automatic Transmission Tester

T - FITTING
2.
Attach the pressure gauge to the

control pressure outlet at the trans-

mission (Figs. '., and 7).

3.
Firmly apply the parking brake

and start the engine.

On a vehicle equipped with a vacu-

um brake release, apply the service

brakes. The parking brake can not be

used because the brake automatically

VACUUM DIAPHRAGM UNIT

CLIP

I

| CONTROL PRESSURE TAKE-OFF HOLE

D2041-A

FIG. 6—Typical Vacuum

Diaphragm and Control Pressure

Connecting Point
releases when the transmission selec-

tor lever is moved to a drive position.

4.
Adjust the engine idle speed lo

the specified rpm. If the engine idle

speed cannot be brought within limits

by adjustment at the carburetor idle

adjustment screw, check the throttle

and downshift linkage for a binding

condition. If the linkage is satisfacto-

ry, check for vacuum leaks in the

transmission diaphragm unit (Fig. 8

or 9) and its connecting tubes and

hoses.
Check all other vacuum oper-

ated units (such as the power brake)

for vacuum leaks.

VACUUM UNIT CHECK

NON-ALTITIDE

COMPENSATING TYPE

To check the vacuum unit for dia-

phragm leakage, remove the unit from

the transmission. Use a distributor

D1840-A

FIG. 8—Testing Transmission

Vacuum Unit for Leakage

VACUUM DIAPHRAGM

D 1643 -C

FIG. 5—Typical Vacuum Test

Line Connections
FIG.
7—Vacuum
Diaphragm and Control and TV Pressure Connecting

Points—C6 Transmissionprocarmanuals.com

07-01-06
General Transmission Service

07-01-06

MAKE MARK HERE

BELLOWS INTACT
BELLOWS FAILED

FIG. 9—Checking Vacuum Unit Bellows

tester equipped with a vacuum pump

(Fig. 8). Set the regulator knob so

that the vacuum gauge reads 18 inches

with the end of the vacuum hose

blocked off.

Then connect the vacuum hose to

the transmission vacuum unit. If the

gauge still reads 18 inches, the vacuT

urn unit diaphragm is not leaking. As

the hose is removed from the trans-

mission vacuum unit, hold a finger

over the end of the control rod. When

the hose is removed, the internal

spring of the vacuum unit should push

the control rod outward.

ALTITUDE

COMPENSATING-TYPE

The vacuum diaphragm should be

checked for ruptured or damaged bel-

lows.
Check the diaphragm assembly

as follows:

1.
Remove the diaphragm and

throttle valve rod from the transmis-

sion.

2.
Insert a rod into the diaphragm,

making sure that the rod is buttonec

in the hole. Make a reference mark on

the rod where it enters the diaphragm

hole.

3.
Hold the assembly in such a way

that the end of the rod is resting on

the weighing surface of a scale (Fig.

9).

4.
Gradually press down on the dia-

phragm assembly until the rod is

pressed into the diaphragm body. If

the reference mark on the rod is still
visible with 12 pounds of force regis-

tered on the scale, the bellows are in-

tact. If the mark disappears before 4

pounds of force is exerted, the bellows

have failed and the diaphragm must

be replaced. If the bellows are intact,

then perform various pressure checks.

SHIFT POINT CHECKS

Check the minimum throttle up-

shifts in D. The transmission should

start in first gear, shift to second, and

then shift to third, within the shift

points specified in the specification

section.

While the transmission is in third

gear, depress the accelerator pedal

through the detent (to the floor). The

transmission should shift from third to

second or third to first, depending on

the vehicle speed.

Check the closed throttle downshift

from third to first by coasting down

from about 30 mph in third gear. The

shift should occur within the limits

specified in the specification section.

When the selector lever is at 2, the

transmission can operate only in sec-

ond gear.

With the transmission in third gear

and road speed over 30 mph, the

transmission should shift to second

gear when the selector lever is moved

from D to 2 to 1. The transmission

will downshift from second or third to

first gear when this same manual shift

is made below approximately 25 mph

with a C4 transmission, 30 mph with
D 1791.A

a C6 transmission or 35 mph with an

FMX transmission. This check will

determine if the governor pressure and

shift control valves are functioning

properly.

During the shift point check opera-

tion, if the transmission does not shift

within specifications or certain gear

ratios cannot be obtained, refer to the

Ford Car and Truck Diagnosis Manu-

al to resolve the problem.

AIR PRESSURE CHECKS

A NO DRIVE condition can exist,

even with correct transmission fluid

pressure, because of inoperative

clutches or bands. Erratic shifts could

be caused by a stuck governor valve.

The inoperative units can be located

through a series of checks by subst-

ituting air pressure for the fluid pres-

sure to determine the location of the

malfunction.

To make the air pressure checks,

drain the transmission fluid and re-

move the oil pan and the control valve

body assembly. The inoperative units

can be located by introducing air pres-

sure into the transmission case passa-

ges leading to the clutches, servos, and

governor (Figs. 10, 11 or 12).

HYDRAULIC SYSTEM BENCH

TESTS (FMX TRANSMISSION)

After the transmission has been as-

sembled and is ready for installationprocarmanuals.com

07-01-07

General Transmission Service

07-01-07

PUMP IN

INTERMEDIATE

SERVO RELEASE
REVERSE AND

HIGH CLUTCH

INTERMEDIATE

SERVO APPLY

GOVERNOR PRESSURE

TO VALVE BODY
FORWARD

CLUTCH

PUMP OUT

CONVERTER IN

CONTROL

PRESSURE

TO PRIMARY

THROTTLE VALVE

PRIMARY THROTTLE

PRESSURE-TO-VALVE

BODY

PRIMARY THROTTLE

VALVE EXHAUST
LOW AND

REVERSE SERVO

CONTROL PRESSURE

TO GOVERNOR

D1841-A

FIG. 70—Case Fluid Passage Hole Identification—C4 Automatic
FRONT PUMP FRONT GOVERNOR

DISCHARGE CLUTCH OUTPUT

FRONT FROM

PUMP CONVERTER REAR

INTAKE SERVO
REAR

CLUTCH

D1932-A

FIG. 12—Case Fluid Hole

Identification—FMX Transmission

in the vehicle, check the hydraulic sys-

tem to make sure it is operating prop-

erly. These hydraulic tests can be

made on the bench so that most mal-

functions of the system can be cor-

rected before the transmission is in-

stalled in the vehicle.

TESTING TOOL

INSTALLATION

SERVO RELEASE

SERVO APPLY
PUMP SUCTION REVERSE-HIGH FORWARD CLUTCH

APPLY APPLY
CONVERTER CHARGE

PUMP PRESSURE

TV PRESSURE

LINE PRESSURE

TV PRESSURE

EXHAUST

-S>*REVERSE CLUTCH

GOVERNOR PRESSURE CONTROL PRESSURE

OUT PUT GOVERNOR
APPLY
1.
Install a plug in the filler tube

hole in the case or pan, and pour

about four quarts of clean transmis-

sion fluid into the transmission

through the speedometer gear open-

ing.

2.
Remove the vacuum diaphragm

unit and the diaphragm unit control

rod, and reinstall the vacuum unit if

these parts had been previously in-

stalled.

Tool-7003

D1587-B
D1933-A

FIG.
7
7—Case
Fluid Passage Hole Identification—C6 Automatic
FIG. 73—Bench Testing Tool

Installation—Typicalprocarmanuals.com

07-01-08
General Transmission Service

07-01-08

3.
Install the bench testing tool on

the transmission.

4.
Remove the
1/8-inch
pipe plug

at the transmission case. Turn the

front pump in a clockwise direction at

75-100 rpm until a regular flow of

transmission fluid leaves the hole in

the transmission case. This operation
bleeds the air from the pump.

5.
Install the pressure gauge (77820

or T57L-77820-A) as shown in Fig.

13.

PRESSURE TESTS

Turn the front pump at 75-100 rpm
and note the gauge readings. The

pressure readings on the bench test

must be within the limits as outlined

in Figure 13, for the engine idle check.

If pressure gauge readings are with-

in limits in all selector lever positions,

install the vacuum diaphragm control

rod unit.

COMMON ADJUSTMENTS AND REPAIRS

TRANSMISSION FLUID DRAIN

AND REFILL

Normal maintenance and lubrica-

tion requirements do not necessitate

periodic automatic transmission fluid

changes.

If a major repair, such as a clutch

band, bearing, etc., is required in the

transmission, it will have to be re-

moved for service. At this time the

converter, transmission cooler and

cooler lines must be thoroughly

flushed to remove any dirt.

When filling a dry transmission and

converter, install five quarts of fluid.

Start the engine, shift the selector

lever as outlined below, and check and

add fluid as necessary.

Following are the procedures for

partial drain and refill due to in-

vehicle repair operation.

C4 TRANSMISSION

1.
On PEA models, disconnect the

fluid filler tube from the transmission

oil pan to drain the fluid.

On PEB and PEE models, loosen

the pan attaching bolts to drain the

fluid from the transmission.

2.
When the fluid has stopped

draining from the transmission, re-

move and thoroughly clean the pan

and the screen. Discard the pan gas-

ket.

3.
Place a new gasket on the pan,

and install the pan on the transmis-

sion.

4.
On PEA models, connect the

filler tube to the pan and tighten the

fitting securely.

5.
Add three quarts of fluid to the

transmission through the filler tube.

6. Run the engine at idle speed for

about two minutes, and then run it at

fast idle speed (about 1200 rpm) until

it reaches it's normal operating temp-

erature. Do not race the engine.

7.
Shift the selector lever through

all the positions, place it at P, and

check the fluid level. The fluid level

should be above the ADD mark. If
necessary, add enough fluid io the

transmission to bring the level be-

tween the ADD and FULL marks on

che dipstick. Do not overfill the trans-

mission.

FMX OK C6

TRANSMISSION

1.
Raise the vehicle on a hoist or

jack stands.

2.
Place a drain pan under the

transmission.

3.
Loosen the pan attaching bolts

to drain the fluid from the transmis-

sion.

4.
After the fluid has drained to the

level of the pan flange, remove the

rest of the pan bolts working from the

rear and both sides of the pan to

allow it to drop and drain slowly.

5.
When the fluid has stopped

draining from the transmission, re-

move and thoroughly clean the pan

and the screen. Discard the pan gas-

ket.

6. Place a new gasket on the pan,

and install the pan on the transmis-

sion.

7.
Add three quarts of fluid to the

transmission through the filler tube.

8. Run the engine at idle speed for

about two minutes, and then run it at

fast idle speed (about 1200 rpm) until

it reaches normal operating tempera-

ture.
Do not race the engine.

9. Shift the selector lever through

all the positions, place it at P, and

check the fluid level. The fluid level

should be above the ADD mark. If

necessary, add enough fluid to the

transmission to bring the level be-

tween the ADD and FULL marks on

the dipstick. Do not overfill the trans-

mission.

OIL COOLER TUBE

REMOVAL AND INSTALLATION

When fluid leakage is found at the

oil cooler, the cooler must be re-

placed. Cooler replacement is de-

scribed in the Cooling System Section

of Group 11.
When one or more of the fluid

cooler steel tubes must be replaced,

each replacement tube must be fabri-

cated from the same size steel tubing

as the original line.

Using the old tube as a guide, bend

the new tube as required. Add the

necessary fittings, and install the tube.

After the fittings have been tight-

ened, add fluid as needed, and check

for fluid leaks.

VACUUM DIAPHRAGM

ADJUSTMENT NON-ALTITUDE

COMPENSATING TYPE

The C4 and C6 transmissions are

equipped with an adjustable vacuum

diaphragm assembly. A similar ad-

justable diaphragm has been released

for service with the FMX transmis-

sion. However, the FMX service dia-

phragm is not interchangeable with

that used on C4 and C6 models.

The vacuum diaphragm assembly

has an adjusting screw in the vacuum

hose connecting tube (Fig. 14).

SPRING

SEAT

THIS CLEARANCE CHANGED

BY ADJUSTING SCREW

D1830-A

FIG. 14—Adjustable Vacuum Unit

The inner end of the screw bears

against a plate which in turn bears

against the vacuum diaphragm spring.

All readings slightly high or all

readings slightly low may indicate the

vacuum unit needs adjustment to cor-

rect a particular shift condition.procarmanuals.com

07-01-09

General Transmission Service

07-01-09

For example, on a C4 transmission,

if the pressure at 10 inches of vacuum

was 120 psi and the pressure at 1.0

inch of vacuum was 170 psi, and up-

shifts and downshifts were harsh, a di-

aphragm adjustment to reduce the di-

aphragm assembly spring force would

be required.

If the pressure readings are low, an

adjustment to increase diaphragm

spring force is required.

To increase control pressure, turn

the adjusting screw in clockwise to re-

duce control pressure, back the adjust-

ing screw out by turning it counte-

rclockwise. One complete turn of the

adjusting screw (360 degrees) will

change idle line control pressure ap-

proximately 2-3 psi. After the adjust-

ment is made, install the vacuum line

and make all the pressure checks as

outlined in the Specification Section.

The diaphragm should not be ad-

justed to provide pressure below the

ranges shown in the Specification Sec-

tion in order to change shift feel. To

do so could result in soft or slipping

shift points and damage to the trans-

mission.

ALTITUDE

COMPENSATING TYPE

The altitude—compensating di-

aphragm is provided with an adjust-

ment screw located in the vacuum

connecting tube (Fig. 15). The adjus-

table feature allows control and TV

pressures to be adjusted (within limits)

to correct soft or harsh shift feel.

Control and TV pressures are in-

creased or decreased by turning the

adjusting screw.

Before replacing or adjusting the di-

aphragm, it must first be determined

that the pressure or vacuum is actual-

ly out of specification and that the

cause of the problem is not due to

other items within the transmission or

vacuum connecting lines.

If the tests outlined in the Specifi-
cation Section have been performed

and pressures are within specification

but shift feel is unsatisfactory, or if

the pressure is too high or too low at

10 inches of vacuum, the vacuum di-

aphragm may be adjusted to improve

the shift feel.

If shifts are excessively harsh, the

diaphragm should be adjusted to re-

duce control pressure by backing off

the adjusting screw (counterclock-

wise).
If shift quality is extremely soft,

control pressure should be increased

by turning the adjusting screw inward

(clockwise).

To adjust the vacuum diaphragm to

compensate for harsh shift quality,

first check control pressure in D, 2

and 1 at 10 inches manifold vacuum

and note the pressure reading ob-

tained. Remove the T-fitting from the

vacuum hose and back off the adjust-

ing screw (counterclockwise) by one

full turn. Each full turn will reduce

control pressure by approximately 2

1/2 psi at 10 inches of vacuum. Test

the vehicle for shift feel. If shift quali-

ty is still harsh, a further adjustment

should be made to reduce control

pressure. However, control pressure

should not be reduced below the speci-

fication shown for 10 inches of vacu-

um. If control pressure has been re-

duced to the low limit and shift feel is

still excessively harsh, the clutches and

band should be checked for correct

operation.

To adjust the vacuum diaphragm to

compensate for extremely soft shifts,

record the control pressure reading at

10 inches of vacuum in D, 2 and 1,

then make an initial adjustment of

one full turn inward (clockwise). Test

the vehicle for shift feel and again ad-

just the diaphragm, if necessary. Con-

trol pressure at 10 inches of vacuum

must not exceed the high limit shown

in the Specification Section.

When the necessary adjustments

have been completed and shift feel is

satisfactory, repeat all the tests out-

ADJUSTING

SCREW

PRIMARY

THROTTLE VALVE
DIAPHRAGM

SPRING

D 1639-A

FIG. 15—Altitude Compensating Type Vacuum Diaphragm
lined in the Specification Section. All

tests must be within specifications.

The adjustable vacuum unit must not

be used to allow for adjusting control

or TV pressures that are out of speci-

fications. If these pressures are found

to be out of specifications the cause

must be determined and corrected bef-

ore making any adjustment.

NEUTRAL START SWITCH

ADJUSTMENT AND

REPLACEMENT—COLUMN SHIFT

There are two types of column-

mounted neutral start switches: A and

B.
Type A switch has a parking brake

brake-release vacuum valve. Type B

switches do not have a vacuum valve.

The switches differ in appearance but

not in operation. Both switches are

actuated by a removable steel lever,

which is installed in the shifter tube

within the steering column assembly.

The following procedures outline the

steps necessary to correctly adjust and

replace the neutral start switch.

SWITCH ADJUSTMENT

Neutral Position

1.
With the selector lever held light-

ly against the neutral stop, attempt to

start the engine. If the engine starts

while holding the lever but does not

start when the lever is released, the

shift linkage should be adjusted. If the

engine does not start in either condi-

tion, adjust the switch.

2.
To adjust the switch in neutral,

place the transmission selector lever

against the stop of the neutral detent

position.

3.
Loosen the two retaining screws

that locate the switch on the steering

column (Fig. 16).

4.
With the selector lever against

the neutral stop, rotate the switch

until a start in the neutral position is

obtained. Then, tighten the switch at-

taching screws to 20 in-lbs torque.

5.
With the switch properly adjust-

ed in neutral, place the selector lever

in the 1 position and push the park

reset button (Fig. 16) to the left

(counterclockwise) until it stops. The

park reset must be performed when-

ever the switch has been adjusted.

Park Position

1.
Place the selector lever in the

park position, release the lever and at-

tempt to start. If the engine does not

start, reset the park adjustment.procarmanuals.com