start stop button FORD MUSTANG 1969 Volume One Chassis

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

07-01-10
General Transmission Service

07-01-10

2.
To adjust the switch for the park

position, place the transmission selec-

tor lever in 1 and push the park reset

button (Fig. 16) to the left (counter-

clockwise) until it stops.

3.
Check the operation of the

switch in each selector lever position.

The starter should engage in only the

neutral and park positions. Be sure to

perform
the
park reset
if for any rea-

son
the
neutral switch
is
adjusted.

If,
after performing
the
switch
ad-

justments,
the
starter still will
not en-

gage
in the
neutral
or
park positions,

replace
the
switch. Never replace
the

neutral switch until
the
switch adjust-

ments have been made.

SWITCH REPLACEMENT

1.
Disconnect the neutral start

switch wires at the plug connector.

2.
Disconnect the vacuum hoses, if

so equipped.

3.
Remove the two screws securing

the neutral start switch to the steering

column and lift the switch from the

column.

Check the column to be sure the

metal switch actuator is secure to the

shift tube and that it is seated as far

forward against the shift tube bearing

as is possible. Also check for a broken

or damaged actuator. If it is broken

or damaged, replace it as shown in

Figure 17.

4.
Before installing a new switch to

the column, check to see that the red

neutral position gauge inserted in the

neutral pinning hole. If the pin is

missing, align the two holes at the

neutral pinning hole on top of the

switch and install a No. 43 drill or

0.092-0.093 inch gauge pin.

5.
While holding the selector lever

against the stop in the neutral detent
ACTUATOR LEVER INSTALLED

WHEN INSTALLING
THE
ACTUATOR

LEVER
BE
SURE THAT
IT
1$ SEATED

AS
FAR
FORWARD AGAINST
THE
SHIFT

TUBE BEARING
AS IS
POSSIBLE.
FORWARD

D2019-A

FIG. 17—Removing
or
Installing Neutral Start Switch Actuator Lever

position, place the switch on the col-

umn and install the two attaching

screws. Tighten the screws to 20 in-lbs

torque.

6. Remove the gauge pin (or No.

43 drill if used).

7.
Connect the switch wires to the

plug connector and check for a start

in the neutral position. The starter

should engage with the selector lever

against the neutral stop. If not, loosen

the attaching screws and move the

switch just enough to engage the start-

er. Tighten the screws to 20 in-lbs tor-

que.

8. With the switch properly adjust-
ed in neutral, push the park reset but-

ton (Fig. 16) to the left (counterclock-

wise) until it stops. The park reset

must be performed whenever the

switch has been adjusted or replaced.

9. To adjust the switch for the park

position, place the transmission selec-

tor lever in 1 and push the park reset

button (Fig. 16) to the left (counter-

clockwise) until it stops.

10.
Connect the vacuum hoses to

the switch, if so equipped.

11.
Check the operation of the

switch in each selector lever position.

The starter should engage in only the

neutral and park detent positions.

NEUTRAL SWITCH-TYPE
A

(USED
ON
VEHICLES WITH VACUUM

OPFRATED PARKING BRAKE)
NEUTRAL SWITCH-TYPIE
B

(USED
ON
VEHICLES WITHOUT VACUUM

OPERATED PARKING BRAKE)

ATTACHING

FIG.
16—Ad
justing Neutral Switch—Column Shift
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