1973 OPEL GT-R Service Manual

78. 161973 OPEL SERVICE MANUAL
POWER FLOW
- 3rd SPEED
MAIN DRIVE GEAR (INPUT)
COUNTERSHAFT GEAR UNIT 3rd SPEED GEAR
3rd SPEED GEAR
GEAR SHIFTER SLEEVE
GEAR SHIFTER SLEEVE CARRIERCOUNTERSHAFT GEAR UNIT GEAR DRIVE
3rd SPEED GEAR
GEAR SHIFTER SLEEVE
GEAR SHIFTER SLEEVE CARRIER
MAIN SHAFT (OUTPUT)
78-4
Figure 78.4
Third Speed
After synchronizing the speeds of the mainshaft and
the 3rd speed gear, the gear shifter sleeve shifts to the
rear of the transmission and locks the 3rd speed gear
to the mainshaft through the gear shifter sleeve car-
rier. This gear shifter sleeve carrier is internally
splined to the gear shifter sleeve and is externally
splined to the mainshaft. Both the 1st speed gear and
the 2nd speed gear are idling. The reverse idler gear
is
not engaged with any gear and, therefore, it is
idle.
With a 3rd speed gear ratio of
1.366:1, the main drive
gear (input) must turn 1.366 revolutions for every
one revolution of the mainshaft (output).

MANUAL TRANSMISSION78.17POWER FLOW
- 4th SPEED
MAIN DRIVE GEAR (INPUT)
GEAR SHIFTER SLEEVE
GEAR SHIFTER SLEEVE CARRIERGEAR SHIFTER SLEEVE
GEAR SHIFTER SLEEVE CARRIER
MAIN SHAFT (OUTPUT)7E5
Figure 78.5
Fourth SpeedAfter synchronizing speeds of the main drive gear
and mainshaft, the gear shifter sleeve shifts forward
and locks the main drive gear to the mainshaft
through the gear shifter sleeve carrier. This carrier is
internally splined to the gear shifter sleeve and is
externally splined to the mainshaft. The 3rd speed
gear, 2nd speed gear, and the 1st speed gear are all
idling. The
reverse idler gear is not engaged with
any gear and, therefore, it is idle.
With a 4th speed gear ratio of 1.000: 1, the main drive
gear (input) must turn 1.000 revolutions for every
one revolution of the mainshaft (output).

78.181973 OPEL SERVICE MANUAL
POWER FLOW
- REVERSE SPEED
MAIN DRIVE GEAR (INPUT)COUNTERSHAFT GEAR UNIT DRIVE GEAR
COUNTERSHAFT GEAR UNIT REVERSE SPEED GEARREVERSE IDLER GEAR
REVERSE IDLER GEAR
Is+ AND 2nd GEAR SLIDING GEAR
Is+ AND 2nd GEAR SLIDING GEAR,s+ AND 2nd SPEED SLIDING GEAR GUIDE
1st AND 2nd SPEED SLIDING GEAR GUIDE UNITMAINSHAFT (OUTPUT)
Figure 76.6
Reverse SpeedThrough the engagement of the reverse idler gear
with the 1st and 2nd gear sliding gear (mainshaft)
and the countershaft gear unit reverse speed gear, the
drive is bridged between the countershaft gear unit
and the mainshaft through the guide unit. The direc-
tion of the mainshaft is reversed. The guide unit is
located between the 1st and 2nd gear sliding gear and
the mainshaft. The guide unit is internally splined to
the 1st and 2nd gear sliding gear, and it is externally
splined to the mainshaft. The 3rd speed gear, 2nd
speed gear, and the 1st speed gear are all idling. With
a reverse speed gear ratio of -3.3 17: 1, the main drive
gear (input) must turn 3.317 revolutions for every
one revolution of the mainshaft (output). The “-
’sign indicates that the direction of rotation of the
mainshaft is opposite that of the main drive gear.UNIT756

MANUAL TRANSMISSION76.19
DIAGNOSIS
MANUAL TRANSMISSION DIAGNOSIS
ConditionPossible CauseNoisy in Forward Speeds1) Low lubricant level.
2) Incorrect lubricant.
3) Transmission misaligned or loose.
4) Front main bearing worn or damaged.
5) Mainshaft bearing worn or damaged.
6) Countergear or bearings worn or damaged,
7) Main drive gear worn or damaged.
8) Synchronizers worn or damaged.
Noisy in “Reverse”1) Reverse sliding gear or shaft, worn or damaged
Hard Shifting1) Clutch improperly adjusted.
2) Shift shafts, or forks worn.
3) Incorrect lubricant.
4) Synchronizers worn or broken.
Jumping Out of Gear1) Partial engagement of gear.
2) Transmission misaligned or loose.
3) Worn pilot bearing.
4) End play in main drive gear (bearing retainer
loose or broken, loose or worn bearings on
main drive gear and mainshaft).
5) Worn clutch teeth on main drive gear and/or
worn clutch teeth on synchronizer sleeve.
6) Worn or broken blocking rings.
7) Bent mainshaft.
Sticking in Gear1) Clutch not releasing fully.
2) Low lubricant level.
3) Incorrect lubrication.
4) Defective (tight) main drive gear pilot
bearing.
5) Frozen blocking ring on main drive gear cone.
6) Burred or battered teeth on synchronizer
sleeve and/or main drive gear.
MAINTENANCE AND ADJUSTMENTS
ADJUSTING REVERSE GEARSHIFT BLOCKER1. Engage second speed.
2. Adjust selector ring (a) so that ball on lower end
of shift finger has an equal clearance on both sides
when seated into the transmission case extension bolt
hole. See Figure
7B-7.3. Back off selector ring an additional
l/4 of a turn
and tighten lock nut (B). See Figure
7B-7.SERVICING GEARSHIFT LEVER
Removal1. Unscrew console from floor panel, on small con-
sole remove three (3) attaching screws, on large con-
sole remove four (4) attaching screws. The fourth
screw is accessible after removal of the ash tray. See
Figure
7B-8.2. Remove rubber bellows from cover plate and from
below unbutton protective cap arranged around in-
termediate shift lever.

76.201973 OPEL SERVICE MANUAL
GEARSHIF
INTERMEDIATE SHAFT,
.SHIFT
FINGER1SELECTOR LEVER
JT “B’
78-7Figure’7B.7 Reverse Gearshift Blocker Adjustment
Figure
78-B3. Unhook tension spring of gearshift lever and, after
removal of retaining washer, push pivot pin out of
intermediate shift lever. See Figure
7B-10.1. Prior to installation, grease support and spherical
end of shift finger with protective grease.
2. Replace lever, pivot pin, retaining washer, and
tension spring. Reposition protective cap and bel-
lows and button cap from below. Replace console.
3. In
Figuie 7B-11, distance A - 8.07”.Figure 7B-10
7&l 1Figure 78.1 1
4. After installation, check as to whether pull ring
can be lifted up approximately
.04 to .08”, whereby
the stop sleeve must still rest against intermediate
shift lever. Otherwise, loosen threaded pin forBowden control wire attachment. See Figure 7B- 12.
Adjust distance B
- free travel - by lifting up pull
ring, and retighten threaded pin. See Figure 7B- 13.
REPLACING BOWDEN CONTROL WIRE IN
GEARSHIFT LEVER
1. Remove gearshift lever.

MANUAL TRANSMISSION78.2178-12
Figure 78-l 2
Figure
78.132. Knock off gearshift lever button and loosen
threaded pin for Bowden control wire attachment.
See Figure 7B-12.
3. Drive spiral pin and clamping sleeve out of shift
finger tube and stop sleeve. See Figure 7B-14.
4. Remove shift finger and pull Bowden control wire,
together with thrust spring, out of gearshift lever.
5. Oil sliding surface of stop sleeve on shift finger
tube with clutch oil.
6. After installation of thrust spring, attach newBowden control wire first with clamping sleeve.
When doing this, the cutout of stop sleeve in installa-
tion position shows to the left. The spiral pins must
not protrude on either side.
7. Clamp tight Bowden control wire with threaded
pin. Prior to tightening, pull ring must rest on gear-
shift lever tube and clamping block on pull ring.SPIRAL PINS7B-14
Figure 71-14
8. Heat up new gearshift lever knob in boiling water
to 176 degrees F. and push it onto lever tube. Ob-
serve distance A
- .3”, see Figure 7B-15. The gear-
shift lever tube end is provided with transverse
grooves for which reason the old button can no
longer be used.7515
Figure
78-l 5
9. Attach shift finger with spiral pin and install gear-
shift lever.
REPLACING GEARSHIFT LEVER BELLOWS
1. Remove gearshift lever.
2. Knock off gearshift lever button and pull off bel-
lows over pull ring.

78.221973 OPEL SERVICE MANUAL
3. Install new bellows. Adhere to distance A
- 8.07”.
See Figure 7B-I 1.
4. Heat up new gearshift lever knob in boiling water
to 176 degrees F. and push it onto gearshift lever
tube. Adhere to distance A .3”, see Figure
7B-15.The gearshift lever tube end is provided with trans-
verse grooves for which reason the old button cannot
be reused. Install gearshift lever.
REPLACING RUBBER DAMPENING PARTS IN
GEARSHIFT LEVER1. Remove gearshift lever.
2. Knock off gearshift lever button and loosen
threaded pin for Bowden control wire attachment.
3. Remove lower snap ring from gearshift lever tube
and pull tube off shift finger.
4. Take off and replace rubber dampening parts.
5. After installation of tube, tighten Bowden control
wire with threaded pin. Prior to tightening, pull ring
must rest on gearshift lever tube and clamping block
on pull ring. See Figure
7B-15.6. Heat up new gearshift lever knob in boiling water
to 176 degrees F. and push it onto gearshift lever
tube. Adhere to distance A
- .3”, see Figure 7B-15.The gearshift lever tube end is provided with trans-
verse grooves for which reason the old button cannot
be reused.
7. Install gearshift lever.
MAJOR REPAIR
TRANSMISSION REMOVAL1. Remove air cleaner. Remove throttle rod from
carburetor and rear support and disconnect battery.
2. Remove screws from fan shroud.
3. Remove gearshift lever (refer to paragraph on ser-
vicing gearshift lever).
4. Support car with frame or wheel stands in the
front or frame stands in the rear.
5. Loosen front exhaust pipe to manifold flange.
6. Remove clutch cable from fork by pushing fork to
disengage the clutch and unsnap cable from slot.
7. Disconnect both wires from backup lamp switch.8. Disconnect speedometer cable from transmission
case extension housing.
9. Unhook parking brake cable return spring and
remove cable adjusting nut, equalizer, and spacer.
See Figure
7B-16.PARKING BRAKE CABLE
PARKING BRAKE
Figure 78-16 Parking Brake Equalizer and Return
Spring
9. Disconnect drive shaft at central joint and remove
as follows: See Figure
7B-16.a. Disconnect parking brake cable equalizer from
rod.b. Mark the mating parts of U-Joint and the drive
pinion extension shaft flange.
c. Loosen bolt locks and remove bolts or nuts.
d. Work propeller shaft slightly forward, lower rear
end of shaft and slide assembly rearward. Remove
thrust spring.
e. Install a plug in the rear of the transmission to
prevent loss of lubricant.
10. Remove rear engine mount bolts and lower trans-
mission as far as possible.
11. Remove transmission case to clutch housing at-
taching bolts and remove transmission.
INSTALLATION OF TRANSMISSION WITH
ENGINE IN CAR1. Make certain main drive gear splines are clean and
dry. Also, make certain the transmission is in Neu-
tral so that the main drive gear splines may be in-
dexed when making the installation.
2. Install transmission and support weight while in-
stalling transmission case to clutch housing bolts.
3. Install rear engine mount.
4. Install propeller shaft, align, and tighten U-Joint
to pinion flange U-Bolt nuts and torque to 11 lb. ft.

MANUAL TRANSMISSION70.235. Attach clutch cable.
6. Perform clutch lash adjustment. See Clutch, Sec-
tions A and B for adjustment procedure.
7. After overhaul of transmission, refill with
2- l/2pints of SAE 80 or SO-90 multi-purpose gear Iubri-
cant.
REMOVING AND INSTALLING SPEED0 DRIVEN
GEAR
(WITH TRANSMISSION REMOVED)
Removing Speedo Driven Gear Assembly1. Use wrench to unscrew speed0 angular drive hold-
ing nut and remove speedo angular drive.
2. With Special Tool J-22926 and Slide Hammer
J-7004- 1, remove speedo driven gear lock pin which
retains speed0 driven gear assembly in transmission
case extension housing.
3. Using Special Tool J-22929 and Slide Hammer
J-7004- 1, remove speed0 driven gear assembly. Tool
J-2292? screws onto the speedo driven gear guide
making it possible to remove the guide and assembly
without damage to the transmission case extension
housing.
Installation of Speedo Driven Gear Assembly1. Using Special Tool J-22929 install speedo driven
gear assembly into transmission case extension hous-
ing. It may be necessary to tap lightly on tool
J-22929 when installing assembly. Be sure speedo
driven gear lock pin hole on guide lines up with hole
in transmission case extension housing. Also, rotate
mainshaft at output end when inserting speed0
driven gear assembly to insure that driven gear
meshes properly with speed0 drive gear on main-
shaft.2. Install speed0 driven gear lock pin into transmis-
sion case extension housing by tapping pin lightly.
3. Install speed0 angular drive by tightening speedo
angular drive to holding nut.
REPLACING BUSHING IN SELECTOR LEVER
(TRANSMISSION AND GEARSHIFT LINKAGE
REMOVED)
Removal1. Remove snap ring from bushing. See Figure 7B-
17.2. Using a suitable brass drift drive out bushing from
snap ring side. See Figure
7B-19.SNAP RING
Figure 78.17 Snap Ring on Selector Intermediate
Lever Bushing
Figure 78.19 Removing Bushing From SelectorIntermediate Lever
Installation1. Using a suitable tool drive in bushing up to stop.
Install bushing in opposite direction of removal with
the cutout in the bushing facing upwards. See Figure7B-
19.2. Install snap ring onto bushing.
TRANSMISSION DISASSEMBLYMaintain the respective positions of all mating parts
during overhaul.