1973 OPEL 1900 manual transmission

7C- 361973 OPEL SERVICE MANUAL
CONTENTS
Subject
DESCRIPTION AND OPERATION:
Description of the Opel Three-Speed Automatic,Transmission....................................................................
Principles of Operation....................................................
ComponentOperation
andLocation............................
Mechanical Operation......................................................
Hydraulic Control Units and Valves............................H,y&aulic Operation..........................................................
DIAGNOSIS:
Sequence for Trouble Diagnosis..................................
Checking
Procedures........................................................
ExternalOil
Leaks..............................................................
Trouble
DiagnosisChart..................................................
Hydraulic Pressure
Checks............................................
MAINTENANCE AND ADJUSTMENTS:
Detent Cable Adjustment..............................................
ServicingSelector
Lever..................................................
MAJOR REPAIR:
Transmission Removal and Installation
AllModels........................................................................
Removalof
OilPan............................................................
RemovalofValveBody....................................................
Removalof
ServoPiston................................................
Removalof
Selector
LeverandShaft........................
RemovalofModulatorAssembly..................................
RemovalofDetentValveAssembly............................
RemovalofExtensionHousing......................................
Removal of Speedometer Drive Gear, Governor
Body and Governor Hub..............................................
Removal of Converter Housing, Oil Pump, Reverse
and Second Clutch Assembly..................................
Removal of Third Clutch Assembly, Planetary
Carrier Assembly, Reaction Sun Gear and Drum
Assembly and Low Bank............................................
Disassembly, Inspection and Reassembly of
Converter Housing, Oil Pump and Reverse Clutch
Disassembly, Inspection and Reassembly of
SecondClutch
................................................................
Disassembly, Inspection and Reassembly of
ThirdClutch....................................................................
Disassembly, Inspection and Reassembly of
Planetary Carrier
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Figure 7C-1 Quadrant In Park Position -Opel 1900
and Manta7C- 381973 OPEL SERVICE MANUAL
R
- Reverse enables the vehicle to be operated in a
reverse direction.
N
- Neutral position enables the engine to be
started and operated without driving the vehicle.
D
- Drive range is used for all normal driving
conditions and maximum economy and has three
gear ratios. Downshifts are available for passing
by depressing the accelerator partially at lower
car speeds and through the “detent” at higher car
speeds.
S or 2
- Second range adds new performance for
hilly terrain. It has the same starting ratio as Drive
range, but prevents the transmission from shifting
above second gear to retain second gear for
acceleration or engine braking as desired. Second
range can be selected at any vehicle speed, but
should not be used above the speed shown m the
Owner’s Manual. This is to prevent over-speeding
the engine. The transmission will shift to second
gear immediately and remain in second until the
vehicle speed or the throttle position is changed
to obtajn first gear operation in the same manner
as in Drive range.
L or 1
- Lo range can be selected at any vehicle speed,
but should not be used above the speed shown in the
Owner’s Manual. The transmission will shift to low
(1st) gear immediately and remain in 1st gear regard-
less of vehicle speed or throttle position. This is par-
ticularly beneficial for maintaining maximum engine
braking.
PRINCIPLES OF OPERATION
Torque ConverterThe torque converter acts as a coupling to transmit
engine torque, through oil, to the transmission power
train. It also multiplies the torque from the engine
under certain conditions of input and output speed.
Figure
7C-2 Quadrant in Park Position - GT Models
The quadrant has six positions indicated in the fol-
lowing order: (Opel 1900 and Manta) P,R,N,D,S,
and L (Figure
7C-1); and (GT) P,R,N,D,2, and 1
(Figure 7C- 2).The torque converter used in the Opel three speed
automatic transmission consists of three basic ele-
ments: the pump (driving member), the turbine
(driven or output member) and the stator (reaction
member). See Figure
7C-3. The converter cover is
welded to the pump to seal all three members in an
oil tilled housing.
P
- Park position enables the transmission output
shaft to be locked
- thus preventing the vehicle
from roling either forward or backward. Because
the output shaft is mechanically locked by a
parking
paw1 anchored in the extension housing,
the park position should not be selected until the
vehicle has come to a stop. The engine may be
started in the Park position.Whenever the engine is running, the converter pump
turns at engine speed and acts as a centrifugal pump,
picking up oil at its center, adding energy, and dis-
charging the oil at its outer rim between the blades.
The shape of the converter pump shells and blades
cause the oil to leave the pump spinning in a clock-
wise direction toward the blades of the turbine. Asthere is no mechanical connection between converterpump and turbine, the oil is the only driving force
and strikes the blades of the turbine, transferring the

7C- 401973 OPEL SERVICE MANUAL
ENERGIZING SPRINGS
UTER RACE (CAM)
ROLLER CLUTCHSTATOR
LOCKS UPSTATOR
COUNTER CLOCKWISE FORCES ON CAM, LOCKOVERRUNS
ROLLERS TO INNER RACE
CLOCKWISE FORCES ON CAM CAUSESTATOR ASSEMBLYx.5
ROLLERS TO OVERRUN INNER RACE
Figure 7C-5 Roller Clutch And Stator Assembly
as a fluid coupling, since both the converter pump
and turbine are turning at the same speed, or at a 1:l
ratio.
The torque converter and input shaft actually form
a simple transmission in themselves, however, since
the requirements of an automobile transmission are
greater, some means of providing additional torque,
neutral and reverse, are required. For this reason a
gear set is added behind the torque converter.
Planetary Gears
Planetary gears are used in automatic transmissions
as the basic means of multiplying the twisting force
or torque from the engine. They are so named be-
cause of their physical arrangement and are used
because they permit constant mesh operation, cannot
clash, operate in a minimum of space and distribute
the load over several gears. The simplest planetary
gear set consists of a center or sun gear, internal or
ring gear and a planetary gears called planetary pin-
ions. See Figure
7C-9. The sun gear meshes with theplanetary pinions which rotate freely on their shafts
attached to the planetary carrier. The ring gear
sur-rounds the assembly and meshes with the planetary
pinions. Power flow through the planetary gear set
is accomplished by applying power to one member,
holding another member thus making it a reaction
member and obtaining the transmitted power from
the third member, which can result in any of the
following conditions:
1. Increase torque with a proportional decrease in
output speed.
2. Increase speed with a proportional decrease of
output torque.
3. Reverse direction of rotation.
4. Act as a direct connection for direct drive.
The gear set used in the Opel Three Speed Automatic
transmission is known as a Ravigneaux planetary

causes the sprags to wedge and prevent rotation in
one direction, and to allow free rotation in the oppo-
site direction.7C. 441973 OPEL SERVICE MANUAL
The clutch is released by exhausting the oil from
behind the piston. The release springs push the pis-
ton to the released position, thereby removing the
force from the plates. See Figure 7C-16.Band
A band is used to hold one planetary member sta-
tionary with relation to the other planetary mem-
bers.
!See Figure 7C-19. The band is connected to the
SPR
7C-16Figure
7C-16 Sprag Cage Assembly
Sprag C(utchA sprag clutch is an overrunning clutch which allows
rotation in one direction only and consists of an inner
race, an outer race and the sprag assembly.
The sprag assembly itself consists of sprags, retainer
rings and a spring. See Figure 7C- 16. The sprags are
mounted at intervals between the two concentric re-
taining rings. The spring is located between the rings
and surrounds the ‘narrow portion of the sprags.
One diagonal dimension of each sprag is greater than
the distance between the inner and outer race, while
the other diagonal is less. See Figure
7C-17. This
\ \I’b+ SPRAG
DISTANCE AFigure
7C-17 Sprag Operational Schematictransmissio; case (stationary anchor) and is ope-
rated by a servo piston. One band is used in the Opel
Three: Speed Automatic Transmission and holds the
reaction sun gear and drum stationary in first and
second gear.
BAND\- D7uM
PRESSURE
STATIONARY
PASSAGE
yPlSfON
1 y””SERVO BODY RELEASE SPRING
7c19
Figure
7C-19 Band Application
COMPONENT OPERATION AND LOCATIONThe power flow and principles of operation of the
Opel Three Speed Automatic Transmission power
train are most easily understood when each unit is
considered separately with a part by part build up of
the unit.
The torque converter is connected to the engine by
means of a flex plate which is bolted directly to the
engine crankshaft and to the converter cover. The
converter cover is welded to the converter pump
member which provides a direct connection of the
engine to the converter. The converter pump hub tits
into the transmission oil pump driving the oil pump
whenever the engine is operating. See Figure
7C-20.The input shaft is splined into the hub of the turbine,
delivering the converter’s output torque to the trans-
mission gear train. See Figure
7C-21.

712.461973 OPEL SERVICE MANUAL___-.. _~--- ..- -_.-. -
THIRD CLUTCH ASSEMBLY7D22
Figure 7C-22 Third Clutch Drum, Piston and Springs, Clutch Plates,
Input Sun Gear. Sprag Race And Retainer Assembly
The stator shaft is an integral part of the transmis-
sion oil pump and supports the stator assembly at the
inner race of the roller clutch assembly.
The input shaft is welded to the third clutch drum.
The sprag outer race is splined to the third clutch
drum and the inner race is splined to the input sun
gear. See Figure
7C-22.The second clutch assembly is supported by the oil
pump hub. The second clutch composition plates are
splined to the outside of the third clutch drum, mak-
ing the third clutch drum the hub for the second
clutch. The ring gear is splined to the second clutch
drum. See Figure
7C-23.The reverse clutch piston assembly is housed on the
back side of the oil pump body. The reverse clutch
steel plates are splined to the transmission case and
the composition plates are splined to the outside of
the second clutch drum. See Figure
7C-24. The re-
verse clutch serves to hold the 2nd clutch drum and
ring gear stationary in reverse range.
The ring gear surrounds the planetary carrier and
the teeth mesh with the front portion of the long
pinions. The reaction sun gear is pressed into the
reaction sun gear drum. See Figure
7C-25. The low
band is wrapped around the reaction sun gear drum
to function as the holding member for the reaction
sun gear.

7C- 481973 OPEL SERVICE MANUAL
INPUT SUNRING
GEAR ASSY.GEARPLANETARY
CARRIERASSY.REACTION SUNtow
GEAR 8 DRUMBAND
Figure 7C-25Planetary Gears
The planetary pinion shafts which support the plane-
tary pinions are secured to the planetary carrier by
means of a lock plate at the rear of the planetary
carrier preventing the pinion shafts from rotating or
working loose. The lock plate is secured to the car-
rier by screws.
The planetary carrier is welded to the output shaft,
therefore, the directional movement of the carrier
delivers the transmission’s torque to the output shaft.
The governor hub is splined to, and driven by, the
output shaft. See Figure 7C-26. A governor body is
bolted to the governor hub. The speedometer drive
gear is also driven by the output shaft, and is secured
to the shaft by a retaining clip.
MECHANICAL OPERATIONThe following information describes how engine
torque is transmitted through the Opel Three Speed
automatic transmission for each selected position on
the quadrant. In every case, with the engine running,
torque is transmitted via the flex plate and converter7G25
cover to
tht? pump member of the converter. The
converter is always tilled with oil from the transmis-
sion’s oil pump, and the converter pump member
transmits the torque through oil to the driven mem-
ber of the converter. Power to the transmission is
then transmitted via the input shaft and third clutch
drum. See Figures
7C-48 through 7C-52.
HYDRAULIC CONTROL UNITS AND VALVESPreviously, the mechanical aspects of the transmis-
sion operation have been described, including refer-
ence to various clutches and the low band being
applied. The following describes, in detail, the hy-
draulic system that applies the clutches and band,
and which controls the manually selected and auto-
matic shifts.
A hydraulic pressure system requires a source of
clean hydraulic fluid and a pump to pressurize the
fluid. Opel Three Speed Automatic transmission uses
a gear type pump which draws oil through a screen
located in the sump. See Figure
7C-29. Since the
pump drive gear is keyed to the converter pump hub,
it turns whenever the engine is operating and turns
the driven gear, which causes the oil to be lifted from

AUTOMATIC TRANSMISSION7c-51VACUUM MODULATOR7c31
Figure 7C-31 Vacuum Modulator and Modulator Valve
decrease as car speed increases. For this reason, gov-
ernor pressure (which is a function of car speed) is
directed to the area between the two different diame-
ter spools at the outboard end of the valve. As gover-
nor pressure increases, it creates an outward force on
the modulator valve and in effect reduces the spring
force of the modulator assembly.
The modulator assembly consists of two chambers
separated by a diaphragm. The chamber toward the
valve is open to atmosphere and the other chamber
is connected to engine vacuum. The vacwm cham-
ber also contains a spring. When there is no vacuum
(0” of mercury), the full spring force bears against
the diaphragm and is transmitted to the valve
through a plunger. This is the spring force which
establishes the regulated pressure of the modulator
valve. As the vacuum in the outer chamber increases,
an outward force is created on the diaphragm which
cancels out some of the spring force. This continues
up to
16” of vacuum, at which point the diaphragm
force cancels out the spring force and the modulator
pressure becomes zero.
In summary, the following indicates the function of
the total modulator system in combination with the
pressure regulator system.
In addition, higher car speeds will produce a some-
what lower modulator and line pressure for any
given vacuum by virtue of the governor pressure
acting on the modulator valve.
Engine
TorqueLow
High
VacuumHigh
Low
Modulator
PreSSWe
LowHigh
LineLOW
HighModulator pressure is then directed to:
Pressure regulator boost valve.
I - 2.Shift control.
2
- 3-Shift control valve by way of the 3 - 2 control
valve.Detent Valve.
I - 2 Accumulator Va!ve.
Low Speed Downshift Timing Valve.
Detent Pressure Regulator ValveThe regulating action of the Detent Pressure Regula-
tor Valve is essentially the same as for the Modulator
Valve, except that it regulates a constant pressure.
See Figure
7C-32. The feed port, regulating port and
exhaust port all function in the same manner as the
Modulator Valve. Since the force set up by the pres-
sure in the regulating port acts only against a
fixedspring force, the resulting detent pressure is con-
stant. The detent regulator pressure is directed to the
Detent Valve and to the Manual Low and Reverse
Control Valve.
DET. PRESS.,REG.
i7G3-2
Figure 7C-32 Detent Pressure Regulator Valve
l-2 Accumulator ValveThe
I 2 Accumulator Valve, Figure 7C-33, is used
to establish a desired pressure to ultimately control
the rate of apply of the second clutch during a
I to
2 upshift. Here again, the regulating action is essen-
tially the same as for the Modulator Valve or Detent
Pressure Regulator Valve.

AUTOMATIC TRANSMISSIONlC- 53
Manual ValveThe manual valve is mechanically connected to the
shift lever. Its function is to direct hydraulic pressure
to the various circuits to establish the base hydraulic
range of the transmission.
Line pressure is fed to the manual valve. See Figure
7C-35. In “Park” and “Neutral”, the valve seals line
pressure from entering any of the circuits. At the
same time all circuits are open to exhaust so that the
transmission remains in a neutral condition.
In “Reverse”, line pressure is directed to the reverse
clutch piston, boost control valve and the reverse and
manual control valve. All other manual control cir-
cuits are open to exhaust.
MANUAL VALVE
;i
\2
P RNDILII7D35
Figure
7C-35 Manual Valve
In “Drive” the manual valve directs oil to the gover-
nor, I
- 2 shift valve, 1 2 accumulator valve, and to
the apply side of the low servo piston by way of the
high speed downshift timing valve. The “Reverse”,
“Second”, and “Low” ports are exhausted.
In “Second” the “Drive” circuits remain pressu-
rized. In addition, pressure is supplied to the boost
control valve and to the 2
- 3 shift valve. The “Rever-
se” and “Low” ports are exhausted.
In “Low”, pressure is supplied to the
1 - 2 shift valve
and to the reverse and manual control valve in addi-
tion to the circuits already pressurized in “Drive”
and “Second”. The “Reverse” port is exhausted.
Detent ValveThe function of the detent valve is to cause the trans-mission to shift to a lower gear for additional per-
formance when the accelerator is depressed all the
way.The detent valve is mechanically connected to the
throttle linkage. A spring holds the detent valve in a
retracted position. See Figure
7C-37. Two pressures,
“detent regulator” and “modulator”, are supplied to
the detent valve.
iiiDETENTE2
MODULATORFigure
7C-37 Detent Valve
In the retracted or “part throttle” position, the de-
tent valve directs modulator pressure to the 1 2 and
2 3 shift control valves and to the 3 2 control valve.
In the “through detent” or full throttle position,
modulator pressure is blocked and the passages
previously receiving modulator pressure now receive
detent regulator pressure. In this position, detent
regulator pressure is also supplied to additional ports
of the 1
- 2 and 2 3 shift control valves and the 3
2 control valve.
1 2 Shift Valve
The 1
- 2 Shift and Shift Control Valves determine
whether the transmission is in first or second gear.
See Figure
7C-38. With the shift valve bottomed in
its bore, the valve blocks “Drive” or line pressure
and the second clutch is open to exhaust. The valve
is held in this position by a spring and any modulator
pressure that may be acting against the two end
spools of the 1
- 2 shift control valve.
As the car speed and governor pressure increase, a
force is developed on the end of the shift valve. When
this force is great enough to overcome the spring and
the force of the 1 2 shift control valve, the shift
valve moves, closing the exhaust and opening the line
pressure port to the second clutch port.