Page 381
Removing the gear lever as from chassis No. 99.039.548
) 1, Undo the three screws under the rubber boot and re-
, move the gear lever from the gear lever housing.
2. Pull out the tension pin from the carrier, screw out
the catch stud and remove the spring.
3. Remove the carrier, the bearing and the cover.
1 4. Knock carefully with a plastic hammer on the knob,
so that it will loosen from the gear lever and remove
the carrier, the catch rod and the rubber boot.
5. Remove the lock ring, which holds the hollow lever
2 and the gear lever together and pull out the hollow
| lever with its rubber bushing.
| Replace damaged or weared parts.
j
|
ae
10 VN K : Assembly
t i 1. Fit slot ring, washers and rubber bushings on the hol-
SCAE Bi74s4+—4 low lever.
oa 2. Fit the hollow lever in the gear lever and fit the lock
5 ring.
9. 3. Fit rubber boot, carrier and catch rod, Put the spring
7: Y,
TYG g
S$ 3189
SECTION THROUGH GEAR LEVER HOUSING,
as from chassis Nos. 99.009.989
1. Gear lever
2. Rubber boot
3. Cap
4. Bearing
5. Tension pin
) 6. Bottom part
/ 7. Gear shift rod
8. Bearing
9. Rubber bushing
10, Carrier
\
/
Removing the carrie. spring up to chassis No. 99.039.547
1. Take out the gear lever as above.
. Undo the lock nut and take off the gear lever knob.
3. Insert too! 839122 into the hollow lever and push
down the spring pressing against the carrier tension
pin. Press just enough to relieve the pressure on the
pin. Pull out the pin with pliers and withdraw the tool.
Remove the spring and carrier.
Nn
Reassemble in the reverse order.
Sept. 1973 SAAB 432-5
Page 382
into the hollow lever and screw in the catch stud 1”
(25 mm) see illustration.
4. Fit cover, bearing, carrier and tension pin.
. Press the knob on the gear lever.
6. Fit the gear lever on the gear lever housing.
a
S$ 3190
SECTION THROUGH GEAR LEVER HOUSING, AS FROM
CHASSIS NOS. 99.039.548
Knob
. Carrier
. Catch rod
. Gear lever
Rubber boot
Rubber bushing
. Washer
. Hollow lever
. Slot ring
10. Washer
11. Rubber bushing
12. Washer
13. Lock ring
14. Cover
15. Bearing
16. Gear lever bearing
17. Carrier
18. Tension pin
19. Spring
20. Gear shift rod
21. Catch stud
22. Bottom part
23. Bearing
24. Rubber bushing
WOMNATDHSWNH
432-6 SAE Sept. 1973
Page 383
GENERAL, ROAD TEST AND FAULT DIAGNOSIS
Automatic transmission
The Automatic Transmission consists of a three-element
hydrokinetic torque converter, and a hydraulically oper-
ated gearbox comprising a planetary gear set providing
three forward ratios and reverse.
Operation
‘D' Range
This is provided for use when full performance of the car
is required and when selected gives a first speed start with
automatic up- and down change.
‘2' Range
This is provided for use when only the first two ratios are
required. ;
Automatic change from ‘1’—'2' is also provided. ,
Driving on 3rd is eliminated. Position 2 may not be se-
lected at speeds above 55 mph (90 km/h).
‘1’ Range
This gives manual selection of 1st gear only. When this
gear has been engaged it will remain in engagement until
‘2’ or D’ has been selected.
Jan. 1973
When selected at higher speeds, the transmission imme-
diately changes to 2nd and when the speed has slowed
down to a certain speed the 1st gear will engage.
Position 1 may not be selected at speeds above 90 km/h.
The torque converter
The feature of using a hydraulic converter in conjunction
with a three speed automatic gearbox provides a means
of obtaining a smooth application of engine power to the
driving wheels and additional engine torque multiplica-
tion.
The converter also provides extreme low speed flexibility
when the gearbox is in 3rd gear and, due to the ability of
multiplying engine torque, it provides good acceleration
from very low road speed without having to resort to a
downshift in the gearbox. Torque multiplication from
the converter is infinitely variable between the ratios of
2:1 and 1:1. The speed range, during which torque multi-
plication can be achieved, is also variable, depending upon
the accelerator position.
$2605
TORQUE CONVERTER
The torque converter for use in conjunction with the
gearbox, comprises an impeller connected to the engine
crankshaft, a turbine connected to the input shaft of the
gearbox, and a stator mounted on a sprag type oneway
clutch supported on a fixed hub projecting from the
converter housing.
440-1
Page 384
| The impeller is rotated by the engine and converts the
engine power into hydrokinetic energy. The fluid flows
| from the impeller vanes to the turbine vanes and returns
to the impeller through the stator vanes. The curvature of
the various vanes is so designed that when a speed differ-
ential exists between the impeller and the turbine, the
angle of the fluid flow from the turbine is changed by the
stator vanes in such a way that the discharge of fluid from
the stator assists in driving the impeller. Under such con-
ditions, torque multiplication occurs and varies from 2:1
when the turbine is stalled to 1:1. The torque 2:1 is re-
ceived when the vehicle is held stationary with the en-
gine operating at maximum throttle opening and any one
of the driving ranges selected. The torque 1:1 is received
when the turbine reaches a speed approximately 90 % of
the impeller. When this speed differential between the im-
peller and turbine is achieved, the fluid flow angle from
the turbine is such that the stator is driven in the same
direction as the turbine and the impeller. Under these
circumstances, the converter becomes a fluid flywheel or
coupling and there is no torque multiplication.
$3192
PRINCIPLES OF OPERATION, TORQUE CONVERTER
1. Impeller
2. Turbine
3. Stator
Chain transmission
From the turbin shaft of the torque converter is the pow-
er transmitted via a chain to the input shaft of the trans-
mission.
The gear set
The planetary gear set consists of two sun gears, two sets
of pinions, a pinion carrier and a ring gear. Hetical invo-
lute tooth forms are used throughout, Power enters the
gear set via the sun gear. In all forward gears, power en-
ters through the forward sun gear; in Reverse, power en-
ters through the reverse sun gear. Power leaves the gear
set by the ring gear. The pinions are used to transmit
power from the sun gears to the ring-gear. In Reverse, a
single set of pinions iswused, which causes the firg gear
to rotate in the opposite direction-to the sun gear. In
forward gears, a double set of pinions is used to cause
the ring gear to rotate in the same direction as the sun
gear. The carrier locates the pinions in their correct
positions relative to the two sun gears and the ring gear
(and also forms a reaction member for certain condi-
tions). The various mechanical ratios of the gear set are
obtained by the engagement of hydraulically operated
multi-disc clutches and brake bands. bY
Clutches
Multi-disc clutches operated by hydraulic pistons connect
the converter to the gear set. In all forward gears the front
clutch connects the converter to the forward sun gear; for
Reverse, the rear clutch connects the converter to the re-
verse sun gear.
Jan. 1971
Page 385
OO ae ee ee wees
Dec. 1975
PRINCIPLES OF OPERATION, AUTOMATIC TRANSMISSION
1.
. Front clutch
. Rear clutch
. Front band
|
fit
|
a Gt tS
MASWN
Torque converter
Rear band
One-way clutch
Selector Position Ratio Applied Driving Held
1 Ist Front Clutch Planet
Rear Band Rear sun gear Carrier
Ist Front Clutch Planet
Dand2
One-way Clutch Meatsub gage Carrier
2nd Front Clutch Reverse
Dand 2
Front Band Rear sun gear Sun
D 3rd Front Clutch Rear sun gear
Rear Clutch
R Reverse Rear Clutch Planet
Rear Rand Front sun gear Carrier
APPLICATION OF BANDS AND CLUTCHES FOR THE
VARIOUS SELECTED POSITIONS
sama
440-3
Page 386
Brake bands
Brake bands, operated by hydraulic servos, hold elements
of the gear set stationary to effect an output speed reduc-
tion and a torque increase. In ‘1’ the rear band holds the
pinion carrier stationary and provides the 1st gear ratio
of 2.39:1 and, in Reverse, a ratio of 2.09:1. The front
band holds the reverse sun gear stationary to provide the
2nd gear ratio of 1.45:1.
One-way clutch
In ‘D’, a one-way clutch is used in place of the rear band,
thus also providing a 1st gear ratio of 2.39:1. This one-
way clutch, allowing the gear set to freewheel in 1st gear,
provides smooth ratio changes from 2nd to ‘st.
The mechanical power flow
First Gear (‘1" selected)
The front clutch is applied, connecting the converter to
the forward sun gear. The rear band is applied, holding
the planet carrier stationary; the gear set provides the
reduction of 2.39:1. The reverse sun gear rotates freely
in the opposite direction to the forward sun gear.
First Gear (’D’ or ‘2’ selected)
The front clutch is applied, connecting the converter to
the forward sun gear. The one-way clutch is in operation,
preventing the planet carrier from rotating anti-clockwise;
the gear set provides the reduction of 2.39:1. When the
vehicle is coasting the one-way clutch over-runs and the
gear set freewheels.
MECHANICAL POWER FLOW — FIRST GEAR ‘D’ OR ‘2’
SELECTED
Second Gear (‘D’ or ‘2’ selected)
Again the front clutch is applied, connecting the converter
to the forward sun gear. The front band is applied holding
the reverse sun gear stationary; the gear set provides the
reduction of 1.45:1.
MECHANICAL POWER FLOW — FIRST GEAR ‘1’ SELECTED
MECHANICAL POWER FLOW — SECOND GEAR 'D‘ OR ‘2°
SELECTED
440-4 SAAB Jan. 1971
Page 387
Third Gear (’D’ selected) The hydraulic system
Again the front clutch is applied connecting the converter The hydraulic system contains a pump of the internal/
to the forward sun gear. The rear clutch is applied, con- external gear pattern, picking up fluid from the oil pan
necting the converter also to the reverse sun gear; thus
through a strainer. Automatic control is provided by a
both sun gears are locked together and the gear set rotates centrifugally operated hydraulic governor on the trans-
as a unit providing a ratio of 1:1,
MECHANICAL POWER FLOW — THIRD GEAR ‘D’ SELECTED
Neutral and Park
mission pinion shaft. This governor works in conjunction
with valves in the valve bodies assembly located in the
transmission. These valves regulate the fluid Pressure and
direct the pressure to the appropriate transmission com-
ponents.
The Pump
The pump, driven by the converter impeller, is in opera-
tion whenever the engine is running. This pump, through
the primary and secondary regulator valves, supplies the
hydraulic requirements of the transmission both with the
engine idling and whilst the car is in motion.
The Governor
The governor, revolving with the output shaft is basically
a pressure regulating valve which reduces line pressure to
a value that varies with output shaft (i.e. vehicle) speed.
This variable pressure, known as governor pressure, is
utilized in the control system to effect up and down shifts
through the 1—2 and 2—3 shift valves. Rotation of the
In neutral the front and rear clutches are off, and no pow- governor at low speeds causes the governor weight and
er is transmitted from the converter to the gear set. The valve to be affected by centrifugal force. This outward
front and rear bands are also released.
Reverse (R selected)
force is opposed by an opposite and equal hydraulic force
produced by pressure acting on the regulating area of the
governor valve. The governor valve is a regulating valve
and will attempt to maintain equilibrium. Governor pres-
sure will rise in proportion to the increase in centrifugal
force caused by higher output shaft speed.
The rear clutch is applied, connecting the converter to the As speed increases, the governor weight moves outwards
reverse sun gear. The rear band is applied, holding the plan- centrifugally to a stop in the governor body, when it can
et carrier stationary; the gear set provides the reduction of move no further. When this occurs, a spring located be-
2.09:1 in the reverse direction.
tween the weight and the governor valve becomes effec-
tive. The constant force of this spring then combines
with the centrifugal force of the governor valve, the total
then being opposed by governor pressure, thus rendering
this pressure less sensitive to output shaft speed variations.
Thus, the governor provides two distinct phases of regula-
tion, the first being used for accurate control of the low
speed shift points.
MECHANICAL POWER FLOW — REVERSE GEAR 'R' SELECTED
Jan. 1971
SAAB 440-5
Page 388
The control system
operated by governor pressure acting upon one end and
throttle pressure acting upon the spring end, line pressure
The control system utilizes three basic types of valves: acting, upon differential areas providing “shift speed
regulating valves, shuttle valves and a manual valve. hysteresis’.
Pressure control is provided by the primary and secondary Manual control is provided by the manual valve which,
regulator valves, the former operating in conjunction with according to the position of the selector, directs fluid to
downshift and throttle valve pressure acting upon the or provides an exhaust for, clutch and servo pistons.
spring end and modulated throttle pressure acting on the For ease of reference, all hydraulic circuits are identified
opposite end. by numbers. See table on page 440—19,
Shift control is provided by the 1—2 and 2—3 shift valves
4
/ PRINCIPLES OF OPERATION, FRONT SERVO
. Brake band
Piston, inner
|. Piston, external
. Adjusting screw
Lever
. Push rod
OASwWna
PRINCIPLES OF OPERATION, REAR SERVO
. Brake band
Piston
. Push rod
Lever
. Push rod
|. ‘Adjusting screw
. Locking nut
NOOSWON=
40-6 SAAB
Sept. 1973
Page 389
Operation in ‘N’
With the engine running, the primary regulator valve
regulates line pressure (1) which is directed to the man-
ual valve and throttle valve. It also permits fluid to reach
the secondary regulator valve.
The secondary regulator valve regulates pressure to the
converter and lubrication of the front end of the gear
train (21). Identical pressure (23) is directed to the rear
end of the gear train. The valve returns excess flow (24)
to the oil pan.
Operation in ‘P’
An internal linkage from the manual valve detent lever
engages the parking pawl with teeth formed on the driven
shaft ring gear.
With the engine running, the operation of the hydraulic
system is identical to ‘N’ except that the manual valve
directs line pressure (6) to the rear servo (13).
This arrangement is based upon the design of the hydrau-
lic system without the rear servo or band performing any
function in this selector position.
Operation in 'R’
Pressure control of the front pump is as in ‘P’ or ‘N’ but
in accordance with accelerator pedal depression, throttle
pressure (9) is directed to the spring end of the primary
regulator valve thus increasing line pressure (1) in accor-
dance with torque capacity requirements.
The manual valve directs line pressure (6) through the 1—2
shift valve to the rear servo (13) and line pressure (7)
through the 2—3 shift valve to the rear clutch and front
servo release (15). Due to absence of governor pressure the
shift valves and servo orifice control valve perform no
function in this selector position. The fluid passages (13),
and (15) of other manual valve positions are utilised in
‘R’ to simplify the hydraulic circuit.
Operation in ‘D’ or ‘2’ — First gear
Pressure control of the front pump will be as in ‘R’ but
with the throttle valve in the full throttle position as illus-
trated, throttle pressure (9) regulated by the modulator
valve plunger (8) acts upon the primary regulator valve
Opposing throttle pressure (9), thus modulating line pres-
sure in the interest of shift quality.
The manual valve directs:line pressure (5) to the front
clutch, governor feed and 1—2 shift valve for the subse-
quent 1—2 shift. Line pressure (3) reaches the 2—3 shift
valve for the subsequent 2—3 shift.
Sept. 1973
’ ~~
The front clutch applied in conjunction with the one-way
clutch, permits the car to move off from rest, in first gear.
The hydraulic circuit for 2 (1st gear) is the same as for
position D (1st gear) except that the system pressure
(3) is prevented from reaching the 2nd—3rd shift valve
by a flange on the shift valve.
Operation in ‘D’ or ‘2’ — Second gear
Pressure control by the primary regulator valve will be of
the front pump output. Throttle pressure (8B—9) acts upon
the primary regulator valve as in ‘D’ — first gear.
Shift control is provided by the 1—2 shift valve moving
under influence of governor pressure (2), opposed by
spring force and throttle pressure (10). This permits line
pressure (5) to reach the apply side of the front servo
(19). The front band thus applied, in conjunction with
the front clutch, provides 2nd gear. With the downshift
valve in the forced throttle position as illustrated, forced
throttle pressure (11) acts upon the 1—2 shift valve and
the 2—3 shift valve thus further delaying the upshift (or
providing a 3—2 downshift or a 2—1 downshift at speeds
when there is little governor pressure (2). The hydraulic
circuit for 2 (2nd gear) is the same as position D (2nd
gear) except that the line pressure is prevented from
reaching the 2nd—3rd shift valve from a flange or edge
on the shift valve.
The figure D-2 shows the “‘kick-down” valve actuated.
Operation in ‘D’ — 3rd gear
Pressure control is as in ‘D’ except that in the throttle
valve position shown (minimum throttle) no throttle pres-
sure or modulated throttle pressure acts upon the two
ends of the primary regulator valve.
Shift control is provided by the 2—3 shift valve moving
against spring force under influence of governor pressure
(2). This permits line pressure (3) to reach the rear clutch
(15) and the release side of the front servo through the
servo orifice control valve. When governor pressure (2) is
apparent, the servo orifice control valve closes, forcing
line pressure through a .059 in, (1.49 mm) orifice which
thus affects the relationship between rear clutch apply
and front servo release in accordance with road speed.
Because the release side of the front servo has a larger
area than the apply side, the front servo will disengage
the band. The rear clutch now engaged in conjunction
with the front clutch provides 3rd gear.
The absence of throttle pressure as mentioned above will
SAnes 440-7
Page 390
cause the 2—3 shift valve to move early under influence
of governor pressure, thus providing a low-speed 2—3
shift.
Operation in 1
Pressure control of the front pump will be as in ‘D’ or ‘2’.
The manual valve directs line pressure (5) to the front
clutch, governor feed and 1—2 shift valve. In the position
illustrated, the 1—2 shift valve is subjected to insufficient
governor pressure (2) to overcome spring pressure. The
result is that the valve prevents line pressure (5) from
reaching the apply side of the front servo but line pressure
(6) is open to the rear servo.
| 440-8 SAAB Senor