1973 OPEL GT-R tow

78.261973 OPEL SERVICE MANUAL
4. Remove both first and second speed shifter yoke
and shifter shaft cam.
Removing Main Drive Gear and Mainshaft
Assembly
1. From front of transmission, pull main drive gear
and needle bearing out of transmission. (May be
necessary to rock main drive gear.)
2. From rear of transmission, pull mainshaft assem-
bly and transmission case extension housing out of
transmission. Gear shifter sleeve will be pulled off
gear shifter sleeve carrier by the third and fourth
speed shifter yoke. Remove sleeve from yoke and
keep sleeve with mainshaft assembly. (Make sure
third and fourth speed shoes are not lost.)
Removing Third and Fourth Gear Shifter Shaft.
1. With main shaft assembly out of transmission
case, drive third and fourth gear shifter shaft out
through hole in front of case with brass drift from
rear of transmission through mainshaft assembly
hole in case.
2. Remove third and fourth speed yoke.
Removing Reverse Gear Shifter Shaft and Reverse
Idler Gear
1. Using a brass drift and from the front of the trans-
mission, drive out reverse gear shifter shaft and plug.
See Figure
7B-28. The reverse speed shifter yoke will
remain in transmission case.
Figure 78.28 Removing Reverse Shifter Shaft
2. With Special Tool J-22923 push reverse idler gear
shaft from front toward the rear. Ensure that lock
ball is not lost. See Figure
7B-29.Figure 78.29 Removing Reverse Idler Gear Shaft
3. Take shaft, reverse idler gear and reverse speed
shifter yoke out of transmission case.
Disassembling Mainshaft Assembly
1. Remove mainshaft bearing snap ring from trans-
mission case extension housing groove and remove
mainshaft assembly from housing. See Figure
7B-30.Figure 78-30 Removing Snap Ring From Rear Bearing
Retainer2. Remove loose parts such as mainshaft needle bear-
ing, mainshaft front ring, synchronizer cover, gear
shifter sleeve, shoes, and front synchronizer spring.
The gear shifter sleeve carrier and the first and sec-
ond speed sliding gear guide unit and their respective
gear shifter sleeve and first and second gear sliding
gear are selected assemblies and should be kept
together as originally assembled. See Figure 7B- 31.

iB- 281973 OPEL SERVICE MANUAL
1 ST SPEED
GINEEDLE BEARING-/CLUTCH
SLEEc?iE,-.
SNAP RING_.. ..~~ ~-KEY SPRING,a-37Figure 70-37Figure 7B-39 Pressing Off Small Clutch Hub
7. With Special Tool J-21684, Press Plate, located
below third speed gear, press out gear shifter sleeve
carrier. See Figure
7B-38.2. Install third speed synchronizer cover onto third
speed gear cone.
J-21604
\
2ND SPEED
GE,ARFigure 78.38 Pressing Off Large Clutch Hub and
Needle Bearing Inner Sleeve8. With Special Tool J-21684, Press Plate, located
below second speed gear, press out gear shifter sleevecarrier. See Figure
7B-39.
TRANSMISSION REASSEMBLY
A. Assembling Mainshaft1. From front of the mainshaft install third speedf;cz&mto mainshaft. Gear must turn freely on main-3. Install rear synchronizer spring into rear side of
gear shifter sleeve carrier so that hooked spring end
rests in one of the slots.
4. Using Press Plate J-21684, press gear shifter sleeve
carrier onto mainshaft so that original tooth contact
is obtained. The rear side of gear shifter sleeve carrier
with installed spring should be toward third speed
gear. This rear side of carrier is recessed more than
front side to allow carrier to be pressed almost flush
with synchronizer cover. See Figure
7B-40.3rd
8 4th
Figure 78.40 Securing Third and Fourth Speed Clutch
Hub on Mainshaft With Snap Ring

MANUAL TRANSMISSION78.29
5. Using external snap ring pliers, secure gear shifter
sleeve carrier on mainshaft with snap ring. See Fig-
ure
7B-40.6. From rear of mainshaft, slide second speed gear
onto mainshaft. Gear must turn freely on mainshaft.
See Figure
7B-41.
2ND SPEED
GEAR CONE\
3RD SPEED
GEAR
MAIN
L; SYNCHRONIZER
VER2ND SPEED
GEAR
7B.41Figure
7B-41 Second Speed Gear and Synchronizer
Ring Installed
7. Place second speed synchronizer cover onto sec-
ond speed gear cone. See Figure
7B-41.
8. Install both synchronizer springs into first and
second speed sliding gear guide unit so that hooks of
both springs rest in the same guide unit shoe slot and
the other spring ends are positioned opposite to each
other. See Figure 78-42.
9. Press first and second speed sliding gear guide unit
onto mainshaft so that the original tooth contact is
obtained.
10. Using Tool J-22913, press first speed gear needle
bearing inner sleeve onto mainshaft.
11. Using Tool J-22913, install tirst and second speed
shoes (long style) and install first and second gear
sliding gear (forked groove to rear) onto first and
second speed sliding gear guide unit.
12. Slide first speed gear needle bearing, synchro-
nizer cover, first speed gear, mainshaft washer
(chamfer toward rear), and mainshaft bearing snap
ring onto mainshaft.
13. Press on mainshaft inner bearing using Tool
J-22913. See Figure
7B-43.GUIDE UNIT
SYNCHRONWER SPRING
Figure 78.42 Both Clutch Key Springs Installed
RI
d-J-22913 MAINSHAFT
ASSEMBLY TOOL
---- .
~.
7B.uFigure 78.43 Pressing on Rear Bearing Using Tool
J-22913
14. Insert lock ball in place in mainshaft and place
speedo drive worm gear and speed0 drive gear spring
washer on mainshaft. Secure with speedo drive gear
snap ring.
15. Place mainshaft assembly into transmission case
extension housing up to its stop. Secure with main-
shaft bearing snap ring. See Figure 7%44.

78.301973 OPEL SERVICE MANUAL
SHOULDER OR
SHIFTE
.44Figure 78-46 Installing Reverse Shifter Fork
Figure 78.44 Mainshaft Assembly Secured Into Rear
Bearing Retainer by Snap Ring
16. Place front synchronizer spring in the gear shifter
sleeve carrier. Install (3) third and fourth speed shoes
(short design) and gear shifter sleeve over gear shifter
sleeve carrier along with synchronizer cover. Arrows
on shoes point toward rear of mainshaft. Gear shifter
sleeve yoke groove should be toward front.
17. With sealer, install new gasket onto transmission
case extension housing.
Installing Reverse Idler Gear and Reverse Gear
Shifter Shaft1. Inspect shafts carefully for burrs, and remove with
emery cloth. Burrs on shifter shaft will prevent easy
installation of shifter yoke. Lightly oil with transmis-
sion oil prior to installation. Place lock ball into
reverse idler gear shaft and push shaft through hole
in rear of case and on through reverse idler gear
which should have groove end toward front. See Fig-
ure
7B-46.Continue to drive reverse idler gear shaft forward
with plastic hammer until rear end of shaft is flush
with rear case face.
2. Position reverse speed shifter yoke in groove of
reverse idler gear and install reverse gear shifter shaft
from rear of case with notches up, pushing it through
reverse speed shifter yoke. See Figure
7B-47.3. Install spiral pin to secure yoke to shifter shaft and
drive plug into hole in rear of case.Figure 78.47 Third and Fourth Speed Shifter Shaft
Installed
Installing Mainshaft Assembly and Main Drive
Gear1. Slide mainshaft assembly into transmission case
from rear.
2. From the’front, slide mainshaft front ring and the
mainshaft needle bearing onto the mainshaft. See
Figure
7B-48.3. Install main drive gear through front of transmis-
sion case until main drive (standard part) snap ring
is flush with case.
Installing Third and Fourth Gear Shifter Shaft1. Position third and fourth speed yoke onto gear
shifter sleeve. See Figure
7B-47.2. Insert third and fourth gear shifter shaft through
hole in front of case with notches down, pushing it
through third and fourth speed yoke. Third and

MANUAL TRANSMISSION70.31COUNTER SHAFT GEAR
THRUST WASHER\Figure 76.48 Installing Spacer Ring and Needle
Bearing Onto Mainshaft
fourth speed yoke should be positioned with rounded
notch at shaft hole portion of yoke toward rear. See
Figure 78. 47.
3. Install spiral pin, allowing
i/16” to 5/64” of pin
to protrude.
Installing First and Second Gear Shifter Shaft
1. Inspect shifter shaft carefully for burrs, and
remove with emery cloth. Burrs on shifter shaft will
prevent easy installation of shifter yoke and cam.
Lightly oil with transmission oil prior to installation.
Insert first and second gear shifter shaft through hole
in rear of case with three notches down and toward
rear of transmission, pushing shaft tirst through
firstand second gear shifter yoke, which should be posi-
tioned on first and second gear sliding gear with
shoulder toward front of case. To position first and
second gear shifter yoke on first and second gear
sliding gear, push reverse idler gear forward, engag-
ing the idler gear with the first and second gear
sliding gear. This will make room for positioningfirst and second gear shifter yoke. See Figure
7B-49.2. Continue to drive first and second gear shifter
shaft through shifter shaft cam, which should be
positioned as shown in Figure
7B-50.3. Install spiral pins to secure shifter yoke and shifter
shaft cam to first and second gear shifter shaft.
Installing Selector Shaft
1. Inspect selector shaft carefully for burrs, andFigure
78.49 Countergear Thrust Washers Installed
Figure
78-50 Position of “L” Shaped Selector Dog
remove with emery cloth. Burrs on shaft will prevent
easy installation of intermediate levers. Lightly oil
with transmission oil prior to installation. Insert new
selector shaft oil seals in holes on both sides of trans-
mission case and insert selector shaft into case and
through third, fourth, and reverse intermediate lever.
Third, fourth, and reverse intermediate lever should
be positioned on selector shaft, as shown in Figure
7B-51.2. Continue to push selector shaft through first and
second intermediate lever and through other side of
case. First and second intermediate lever should be
positioned on selector shaft, as shown in Figure 7B-
52. Selector shaft is rotated counterclockwise (when
looking from lever end of selector shaft) from work-
ing position to have spiral pin holes in shaft vertical
and in line with pin holes in intermediate levers. To
rotate selector shaft in this manner, the reverse gear
shifter shaft and its reverse speed shifter yoke must
be pushed rearward so that the reverse idler gear is
against rear of case.

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- 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.