PONTIAC FIERO 1988 Service Repair Manual

700.R4-22 HYDRAULIC DIAGNOSIS
NEUTRAL- ENGINE RUNNING
1 JH001&VOOR4 I Figure 18 Neutral - Engine Running

HYDRAULIC DIAGNOSIS 700.R4-23
NEUTRAL-- ENGINE RUNNING
34 CLU~H - RELEASED 2.4 MlD - RELEASED COlVERTER CLUTCH - RELEASED
REVERSE IMPU CLUTCH - RELEASED LO MD REVERSE CLUTCH - RELEASED OVERRUN CLUTCH - RELEASED
FORWARD CLUTCH - RELEASED LO ROLLER CLUfCH - MOT HOLDING FORWARD tPRAG CLUTCH - Hm HOLDlWG
When the selector lever Is moved to the Neutral IN1 position, the line pressure is directed to the same
areas as in Park, except in Neutral (N) the manual valve directs oil into the Reverse, Neutral, Drive
4, Drive 3 (RN04031 oil is directed to the 2-3 shift valve which directs RND403 oil to the 3-4 relay
valve through the servo feed passaga Oil at these valves is available for use in other ranges.
SUMMARY
The converter is filled from the release side; all clutches and the band are released, At idle, there is
not sufficient T,V. pressure to open the M.T,V. up or M.T.V. down valves.
I JHO176-fQOR4 Figure 20 Neutral - Engine Running

700.R4-24 HYDRAULIC DIAGNOSIS
D-4 FlRST GEAR
1 JH0019-700R1 1 Figure 21 D4 - First Gear

HYDRAULIC DIAGNOSIS 70064-2
FORWARD CLUTCH - APPLIED
D-4-FIRST GEAR
LO ROLLER CLUTCH - HOLDlllO FORWARO SPRRQ CLUTCH - HOLDING
When the selector lever is moved to the Orive {Dl position, the manual valve is repositioned to allow
line pressure to enter the Drive 4 104) passaga Drive 4 oil then flows to the following:
1. Forward Clutch Accumulator, Forward Clutch and Abuse Valve
2. Governor Valve
. 3. 1-2 Shift Valve
4, Accumulator Valve
5. 3-4 Shift Valve
BASIC CONTROL
Drive 4 oil is directed to the forward clutch accumulator where the #I2 checkball seats, routing
forward clutch feed through an orifice. This combines with the forward clutch accumuIator to cushion
the forward clutch
apply,
During "Rock Cyclea' cpnditions (stuck in mud or snow and "Rocking" out), an abuse valve routes
D4 oil to forward clutch feed oil to quicken the apply of the forward clutch.
Driw 4 oil is directed to the 1-2 and 3-4 shift valves, Drive 4 oil is directed to the accumulator valve
and is regulated to a pressure called accumulator pressure; this pressure is directed to the 1-2 and
3-4 accumulator pistons to act as a cushion for the band apply in second gear and overdrive.
'Drive
4 oil is orificed into the gwernor passage, and is regulated to a variable pressure called governor
pressure. Governor pressure increases with vehicle speed and acts against the 1-2, 2-3, 3-4, con-
verter clutch and the 3-2 control valve springs.
In first gear, there could
be sufficient throttle valve plunger travel to increase T.V. pressure enough
to open the MW. up and the M.T.V. down valves. In first gear, MXV. up exerts pressure against governor
pressure at the 1-2, 2-3, 3-4, and converter clutch throttle valves. M.T.V. down pressure is stopped
by a land at the 2-3 and 34 throttle valves,
SUMMARY
The converter clutch is released, the forward sprag dutch is holding, the forward clutch is applied;
the transmission is i'n Drive (Dl Range - First Gear.
I Jn0177-700M Figure 22 D4 - First Gsar

70044-26 HYDRAULIC DIAGNOSIS
D-4 SECOND GEAR
I JCLOOZO.7QQA4 I
Figure 23 D4 - Second Gear

HYDRAULIC PlAONOSlS fOO-R4-27
D-4-SECOND GEAR
FORWARD SPRAE CLUTCH - HOLDlMO 24 BAND - APPLIED FOIWARD CLUTCH - APPLIEP
As both vehicle speed and govanor pressure increase, the force of the governor oil acting on the 1-2
shift valve overcomes the pressure of M.T.V. up oil and the force of the 1-2 throttle valve spring. This
allows the 1-2 shift valve to open and Drive 4 (041 oil to enter the second (2nd) oil passage. This
oil is called second (2nd) oil. Second oil from the 1-2 shift valve is directed to the following:
1. 1-2 Shift Checkbatl (8)
2, 2-4 Servo
3. 1-2 Accumulator Piston
4. Converter Clutch Shift Valve
5. 3-4 Relay Valve
WlC CONTROL
Second ail from the 1-2 shift valve will seat the 1-2 shift checkball (8) forcing 2nd oil through an orifice.
Second oil Is then directed to the 2-4 servo to apply the 2-4 band. At the same time, 2nd oil moves
the 1-2 eccumulator piston against accumulator pressure and the accumulator spring to maintain a
controlled build-up of pressure on the servo during tho 1-2 shift for a smooth bend apply 2nd oil at
the converter clutch shift vatve and the 3-4 relay valve is availabl~ for use in other ranges.
SUMMARY
The converter clutch is released, the 2-4 band is applied, the forward clutch is applied, and the for-
ward spmg clutch is holding; the transmission is in Drive (Dl Range - Second Gear,
dH017B.7OOR4 -
Figure 24 D4 - Second Gear

70bR4-28 HYDRAULIC DIAGNOSIS
D-4 SECOND GEAR
(CONVERTER SIGNAL OIL)

HYDRAULIC DIAGNOSIS 700.R4.29
CO#YEA'TER CLUTCH - APPUEO
FDRWMO CLUTCtl - APPUED
D-4-SECOND GEAR
I Converter Signal 011 1
2-4 BAMD - APPLIED
FORWARD SWAG CLUTCH - HOLDiNQ
NON EC.M. CONTROLLED VEHICLES
As vehicle speed and governor pressure increase, the force of the governor oil acting on the converter
clutch shift valve overcomes the pressure of M.T.V. up oil and the force of the converter clutch T.V.
spring. This allows the converter clutch shift valve to open and 2nd oil to enter the converter clutch
signal
passaga Converter signal oil will exhaust at the T.C.C. sotenoid until a signal is received from
the vehicles external controls.
E.C.M. CONTROLLED VEHICLES
Second oil 'is rerouted into converter clutch signal oil at the bore plugs used in place of the converter
clutch shift valve. Conwrter signal oil exhausts at this solenoid until a signal is received from the vehicles
EC.M.
JHOl7klW14
Figure 26 I14 - Second Gear - Converter Signal Oil

0044.30 HYDRAULIC DIAGNOSIS
D-4 THIRD GEAR -
-lmAwh-
(CONVERTER cum+ APPLIED)
JHOO22-7OOR4
Figure 27 04 -Third Gear - Converter Clutch Applied

HYDRAULIC DfAQNOSIS 70044-31
As both vehicle speed and governor pressure increase, the force of gowrnor oil acting on the 2-3
shift valve overcomes the force of the 2-3 T.V. spring and MXV. up oil, This allows the 2-3 shift valve
to
open and allows RN04D3 oil to enter the 3rd clutch passage.
Third clutch oil from the 2-3 shift valve is directed to the following:
1. 3-2 Exhaust Checkball (4)
2. 3-4 Clutch Piston
3. Third Clutch Accumulator Checkball (2)
4. Third Accumulator Exhaust: Checkball (7)
6. 2-4 Servo 1Release Side)
6. 3-2 Control Valve
D-4-THIRD GEAR
[Converter CItPtch Applied)
COMVERTER CtUTCli - APPLIED FOAWARD CLUTCH - APPLIED
FORWARD SFRAG CLU7CH - HPLDINO 34 CLUTCH - APPLIED
Third clutch oil from the 2-3 shift valve flows past the 3-2 exhaust checkball (4), to the 3-4 clutch
piston. At the same time, third clutch oil is directed past the third clutch accumulator checkball {2),
seats the third accumula'tor exhaust check ball (71, and then into the release side of the 2-4 serva
This third clutch accumulator pressure combined with the servo cushion spring, moves the second
apply piston, in the 2-4 servo, against second oil and acts as an accumulator for a smooth 2-4 band
release and 3-4 clutch apply.
Third clutch oil is present at the 3-2 control valve In preparation of a third gear to second gear shift.
Once the solenoid teceives a signal from the vehicles controls and solenoid is on, convefier clutch
signal oil will shift the converter clutch apply valve, and redirect converter feed oil into the apply passage.
the apply oil flows between the stator shaft and converter hub to charge the converter with oil and
push the converter pressure plate against the converter cwer, causing a mechanical link between
the engine and the turbhe shaft. The rate of apply is controlled by the orifice checkball capsule in
tha end of the turbine shaft.
At tho same time the converter clutch appfy valve will direct converter feed oil through an orifice to
the transmission cooler. Cooler oil is directed to the transmission lubrication sysm.
SUMMARY
The converter clutch is applied*, the forward clutch is applied, tho forward sprag clutch is holding,
the 3-4 clutch is applied and the 2-4 band is released; the transmission is in Drive (Dl Range - Third
Gear (direct drive).
+The converter clwh msy or may not be applied, depending on Aitt calibration and salenoid operation. JHOI 80+7OOA4
Figure 28 D4 - Third Gear - Converter Clutch Applkd