Pontiac FIREBIRD 1972 Service Manual page 1060

76-22 1972 PONTIAC SERVICE M A N U A L
DRIVE RANGE
-
FIRST GEAR
POWER FLOW
Intermediate Clutch
..............................................
Off 1. Forward Clutch (to apply the clutch).
Direct Clutch
.......................................................
Off
Forward Clutch
..................................................
On 2. Governor
Low and Reverse Clutch
........................................
Off
Intermediate Overrun Roller Clutch
................
Locked 3. 1-2 Shift Valve
Low and Reverse Roller Clutch
..........
Free Wheeling
Intermediate Overrun Band
....................................
Off 4. 2-3 Shift Valve
OIL FLOW
Line pressure is fed to:
1. Modulator Valve.
2. Manual Valve.
3. Pressure Regulator Valve.
Also, from the manual control valve, line pressure
becomes R.N.D. oil and is fed to the intermediate servo.
When the range selector lever is moved to Drive (D)
position, the manual valve directs line pressure to the
R.N.D. and drive ports. R.N.D. oil strokes the intermedi-
ate servo so that it is prepared to cushion the 2-3 clutch
for an upshift. The 1-2 accumulator has already been
stroked with line oil to prepare it to cushion the 1-2clutch
for an upshift.
4. Detent Pressure Regulator Valve. Drive oil is directed to and applies the forward clutch and
is directed to the governor assembly, where it is regulated
5. 1-2 Accumulator.
to variable governor oil. Governor oil (which increases
with car speed) is directed to the ends of the 1-2 and 2-3
From the manual control valve, line pressure becomes shift valves, to the manual control valve and to the
drive oil and is fed to: modulator valve.
SUMMARY
The forward clutch is applied and the transmission is in first gear.
DRIVE RANGE
-
SECOND GEAR
POWER FLOW
Intermediate Clutch
..............................................
On
Direct Clutch
....................................................
Off
Forward Clutch
......................................................
On
Low and Reverse Clutch
........................................
Off
Intermediate Overrun Roller Clutch
................
Locked
Low and Reverse Roller Clutch
..........
Free Wheeling
Intermediate Overrun Band
....................................
Off
valve to move to the upshifted position, which allows drive
oil to pass through the valve and leave as 1-2 clutch oil.
1-2 (intermediate) clutch oil is directed to:
1. Intermediate clutch (to apply the clutch).
2. 2-3 Accumulator
OIL FLOW
3. 1-2 Accumulator
As both vehicle speed and governor oil pressure increase,
the force of the governor oil pressure (46 p.s.i. at W.O.T.),
acting as the end of the 1-2 shift valve, overcomes the force
of the 1-2 shift valve spring and modulator shift valve oil
regulated by the detent valve. This allows the 1-2 shift
1-2 clutch oil flows from the 1-2 shift valve, through the
2-3 accumulator and then to the 1-2 accumulator which,
with line oil already stroking it, cushions the intermediate
clutch application.
SUMMARY
Both the forward and the intermediate clutches are applied and the trans-
mission is in second gear.
When in Drive range, the full throttle 1-2 upshift will occur at approxi-
mately 42-49 m.p.h. and the mimimum throttle upshift will occur at
approximately 9-12 m.p.h.