1973 OPEL GT-R oil

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.

7C- 541973 OPEL SERVICE MANUAL
Figure 7C-38 1 2 Shift Valve
To prevent a “hunting” condition of the shift valve,
modulator pressure supply to the second spool of
control valve is cut off as the shift valve opens line
pressure to the second clutch. The oil in this pocket
is exhausted out through the detent passage. An ad-
ditional force keeping the valve in an “upshifted”
position is obtained by line pressure acting on the
larger diameter second spool of the shift valve. Be-
cause of this, even though the governor pressure
might be maintained at a constant pressure after the
valve upshifts, a higher modulator pressure is re-
quired to cause the valve to downshift.
If the accelerator is depressed to the point where the
detent spring force is felt, the vacuum will drop and
the modulator pressure will increase. If the spring
force plus the modulator pressure acting against the
end spool of the shift control valve is great enough
to overcome the governor and line pressure acting on
the shift valve, a “part throttle” forced downshift
will occur. If not, the transmission will remain in the
higher gear.
If the accelerator is depressed through the detent, the
detent valve supplies detent regulator pressure to all
three spools of the shift control valve, a higher down-
shifting force is obtained as compared to the part
throttle condition. Because of this, a “through
detent” forced downshift can be obtained at a speed
higher than for the “part throttle” condition. How-
ever, there is still a limiting speed at which a
“through detent” forced downshift will occur.
If the selector lever is placed in “Manual Low”, line
pressure is supplied directly to the spring pocket
between the valves. Since line pressure can never be
less than governor pressure, the force established by
line pressure on the shift valve plus the spring forcewill move the shift valve to a downshifted position
regardless of car speed.
2 3
,Shift Valve and 3 - 2 Control Valve
The function and operation of the 2 3 Shift and
Shift Control Valves is the same as for the
I 2 valve
except as described below. See Figure
7C-39.The downshifted position establishes “second” gear,
and the upshifted position establishes “third” or
“high” gear.
~ZND CLUTCH*
-I.Figure
7C-39 2 3 Shift Valve and 3 2 Control Valve
Modulator pressure is supplied to the end spool of
the 2
- 3 control valve through the 3 - 2 control valve.
When the shift valve moves to the upshifted position,
line pressure is introduced to the third clutch circuit.
The third clutch circuit also directs pressure to the
end spool of the 3
- 2 control valve.
At light throttle conditions, third clutch pressure
acting on the end of the 3
- 2 control valve moves the
valve against the spring and the force established by
the modulator pressure. This exhausts the modulator
pressure from behind the end spool of the 2
- 3
control valve and the spring is the only remaining
force acting on the shift valve to produce a down-
shift. In this condition, it is not possible to obtain a
“part throttle” forced downshift.
If the accelerator is depressed far enough to cause a
substantial drop in vacuum, the increased modulator
pressure on the 3
- 2 control valve plus the spring will
overc,ome the force of the third clutch pressure. This
feeds modulator pressure back to the 2
- 3 control
valve and a “part throttle” forced downshift will
occur. As with the 1 2 shift valve, there is a limiting
speed at which this can occur.
When the selector lever is placed in “Second”, line
pressure is directed to the spring pocket between the
2
- 3 Shift and Shift Control Valves and the shift

a.Operation of Controls in Neutral Engine Running
Reverse Clutch ReleasedThird Clutch Released
Second Clutch ReleasedSprag LockedLow Band Released
Whenever the engine is running with the selector lever in Neutral, oil is pulled from the sump into the oil pump and is dispensed from the pump under preure.
The pressurized line oil if directed
to the priming valve which bleeds off the air. Line oil is directed to the vacuum modulator YBIYB, to the prexwre regulator valveand
to the manual veIve. The converter is fed through the pressure regulator MIYB. the return oil from the converter being directed through the coalerand back
into the transmisGon’s lubricating system.
Line oil directed
to the vacuum modulator valve becomes regulated to modulator oiland acts on the pressure regulator boosI YBCB. the IDW speed downshift timing
valve. the 1 2 accumulator MIYB. and the detent valve. The modulator oil passes through the detent valve to act 00 the I 2 shift control give. the 3 2 control
valve and the 2 3 shift control valve. Line oil pasres through the manual v&e. and is regulated et the detent preaure regulator valve before being directed to the
Reverseand Low control delve.Summary
The converter is filled. the clutches and
IDW band are released.The transmission is in Neutral.

c. Operation of Controls in Drive Range Second Gear
Reverse Clutch
ReleasedThird Clutch Released
Second Clutch AppliedLow Band Applied
Sprag Over Running
As the vehicle increws speed. the govwnor
allow more drive oil 10 pass through, and this increased pressure, acting on the end of the 1 2 shift
vahre. overcomes the I 2 shift valve spring pressure and allovn drive oil 10 pasr through the valve to feed the second clutch oil parsages.Second clutch oil passes through the second clutch orifice control valve, seating the ball and is metered to the second clutch piRon
to begin to apply
the second clutch, whileportion of the oil is directed
10 the accumulator. As the upper portion of the accumulator fills with second clutch oil. itovercomes the leer prewre of 1 2 accumulator oil and spring at the bottom of the accumulator piston. forcing the piston downward. The upper
portion of the accumulator is now filled, allowing full oil preaure
to the second clutch piEton far the final apply. The accumulator, therefore, acts as a
reservoir
10 produce a damping effect for a smooth second clutch apply and the 1 2 shift.
Second clutch oil from the 1 2 shift
valve is simultaneously directed to the 2 3 shift valve to be used as the oil source for the 2 3 shift.
Summary
The second clutch is on. the band is on, the transmission is in drive range
i second gear.

d. Operation of Controls in Drive Range Third Geat
Reverse Clutch ReleasedThird Clutch-Applied
Second Clutchs AppliedLow Band Released
Sprag Locked
As vehicle speed increases. the governor allows more oil to pass through to act against the wring
at the 2 3 shift valve. This allows the second clutch oil at
the 2 3 shift valve
10 be released and pan through the valve as third clutch oil, directed tothe third clutch piston to apply third clutch. At the same time,
third clutch oil is directed
to the 3 2 control valve. acting against the spring and modulator oil. cutting off modulator oil pressure to the 2. 3 shift controlyalve. Third control oil also is directed to the Reverse and Law control valve and pasts through thevalveasservo release oil to the lowspeed downshift
timing valve. The low speed downshih timing valve is held
open against the spring by increased modulator oil pressure. The oil passes through the valve and
is directed
to the top of the low band sewo. to act with the servo piston spring and force the sel~o piston downward. releasing the low band.
The second clutch is on, the third clutch is on, the band is released. The transmikn is in drive range third gear

e. Operation of Controls in Second Range Second Gear
Reverse Clutch
Re easedThird Clutch Released
Seconds Clutch AppliedLow Band Applied
Sprag Over Running
The
selector lever is moved to the Intermediate position an the quadrant. the manual valve is positioned to allow drive oil and Intermediate oilto pan through the valve. Intermediate oil is directed
to the pressure regulator boost control cavity, seating the check ball at the reverse passage.Intermediate oil is then directed to the pressure regulator valve downward to
increaSe the oil prepare in the circuit. At the same time. the inter.
mediate oil from the manual valve is directed lo the 2 3 shift valve train closing off the supply of third clutch oil in the circuit, which isexhausted
through the Reverse and Low control
valve.
SummaryWith third clutch oil exhausted. the third clutch is off, the second clutch is an, the low band
servo is applied. The transmission is in second
Range Second Gear.

f. Operation of Controls in Low Range First GeaReverse Clutch ReleasedThird Clutch Applied
Second Clutch Released
Low Band Applied
Sprag Locked
When the
selector lever is moved to the low position on the quadrant. the manualvalve is positioned to allow drive oil, intermediate oil and low oil to pass
through the valve. Low oil is directed to the
1 2 shift valve train which acts with the I 2 shift valve spring against governor oil pressure to close off drive
oil from passing into the second clutch passage. At the
same time, low oil is directed to the Reverse and Low control valve and acts against the spring to
allow detent regulated oil at the Reverse and Law control
valve to flow to the 2 3 shift valve, which is bottomed in its bore by intermediate oil pressxeand the valve spring. The detent oil
pazses through the 2 3 shift vahre and into the third clutch oil passages to apply the third clutch and to close off
modulator oil pressure from the 3-2 control valve to the 2 3 shift control valve. Third control oil isalSo directed to the Reverse and Law control
valve.which is held open against its spring by low oil pressure. and closes off the
source of rupply to the servo release pasege. to allow the servo to apply the low
band. Intermediate oil seats the check ball at the Reverse
passage at the presue regulator boost valve cavity and continues to the pressure regulator valve
to increase oil pressure in the circuit.
iThe third clutch in on, the band is on. The transmi&n is in Low Range First Gear

9. Operation of Controls in Reverse
Reverse Clutch -Applied
Second Clutch Released
Sprag LockedThird Clutch. Applied
Low Band. Released
When the selector leer is moved to the Reverse position on the quadrant, the manual
valve ispositioned to allow Revert oil to pars through the manual
valve into the
Reverse oil passage. The reverse oil applies the reverse clutch. and a portion is directed to the priming valve which acts as a damper until the
line is filled. to effect a smooth and firm apply of the
reverss clutch. At the wne time, reverse oil is directed to the pressure regulator boost control valve
cavity to seat the check ball and prevent reverse oil pasring into the intermediate oil passage. It is then directed to the pressure regulator boast valve forcing
Reverse oil is also directed to act on the end of the
Reverse and Law control valve against the spring to allow detent regulated oil to pass through the valveto the 2 3 shift
valve. The detent regulated oil passes through the 2 3 shift valve and into the third clutch oil passages to apply the third clutch. The third
clutch oil
al= acts on the end of the 3 2 control valve against the spring and modulator oil pressure, clodng off the supply of modulator oil to the 2 3
shift control valve. Third clutch oil at the rwerse and low control valve is closed off from
parring through the valve. and into the servo releal~ parrage.Summary
The
reverse clutch is cm and the third clutch is on. The transmission is in Reverse Range.