1988 PONTIAC FIERO Service Repair Manual

700-R4.4 HYDRAULIC DIAGNOSIS
1988 "THM 700-R4" SHIFT SPEED CHART
NOTES: 1. ALL SPEEDS INDICATED ARE IN MILES PER HOUR. CONVERSION TO KPH = MPH x 1.609.
2.
SHIFT POINTS WILL VARY SLIGHTLY DUE TO ENGINE LOADS AND VEHICLE OPTIONS. 3. SPEEDS LISTED WITH + EXCEED 55 MPH.
Figure 2 Speed Shift Chart

HYDRAULIC DIAGNOSIS 700-R4-5
AS A DIAGNOSIS AID, YOU CAN CHECK THE OIL PRESSU BETWEEN LINE PRESSURE AND THE 2ND, 3RD AND 4TH
WHILE DRIVING THE VEHICLE. IF THE PRESSURE
DIFF
LINE PRESSURE TAP
IS ON LEFT
SIDE
Figure 3 Oil Pressure Tap Locations

700-R4-6 HYDRAULIC DIAGNOSIS
L PRESSURE CHECK NFORMAT
PRELIMINARY CHECK PROCEDURE
0 CHECK TRANSMISSION OIL LEVEL 0 CHECK AND ADJUST T.V. CABLE
0 CHECK OUTSIDE MANUAL LINKAGE AND CORRECT
@ CHECK ENGINE TUNE
0 INSTALL OIL PRESSURE GAGE
CONNECT TACHOMETER TO ENGINE
0 CHECK OIL PRESSURE AS FOLLOWS:
Minimum T.V. Line Pressure Check (A) ATTACH PRESSURE GAGE
Set the T.V. cable to specification; and with the brakes applied, take the line pressure readings in the ranges and
at the engine
r.p.m.'s indicated in the chart below.
Full T.V. Line Pressure Check Full T.V. line pressure readings are obtained by tying or holding the T.V. cable to the full extent of its travel; and with
the brakes applied, take the line pressure readings in the ranges and at the engine
r.p.m.'s indicated in the chart below.
MODEL
Line pressure is basically controlled by pump output and the pressure regulator valve. In addition, line pressure is
boosted in Reverse, Second and Lo by the reverse boost valve.
Also, in the Neutral, Drive, Intermediate and Reverse positions of the selector lever, the line pressure should increase
with throttle opening because of the T.V. system. The pressure is controlled by the T.V. cable, the throttle lever and
bracket assembly and the T.V. link, as well as the control valve assembly.
The main line pressure tap plug is located on the left side of the transmission above the outside manual lever.
Figure
4 Oil Pressure Check Procedure

HYDRAULIC DIAGNOSIS 700-R4-7
SECOND 1.62 REVERSE 2.29 THIRD 1 .OO
Figure 5 Clutch Application Chart

700-R4-8 HYDRAULIC DIAGNOSIS
OIL LEAK - Low bolt torque.
- Cut or damaged oil pan gasket.
To Correctly Identify Oil
Leaks, Perform the Following
T.V. Cable Connector - Connector cocked and interfering with
Procedure:
- Connector cracked.
0 Clean all residual oil from - Seal missing, cut or damaged.
the transmission with
elec-
tramotive cleanser or equiv- - Fill tube cracked or damaged.
alent.
- Seal missing, cut, or damaged.
0 Dust the transmission with 0 Electrical Connector - Electrical connector cracked.
leak tracing powder or spray
- Seal missing, cut or damaged.
foot powder.
@ Manual Shaft - Manual shaft nicked or damaged.
Bring the engine to normal
- Manual shaft seal assembly missing, cut
operating temperature.
Turn the engine off and Governor Cover
- Gaps in sealant. (Remove & Reseal.)
let the vehicle set for
Speedo Fitting
- Low bolt torque.
- Seal missing, cut or damaged.
Check for leaks.
@ Servo Cover
Cooler Fittings
- Cracked fitting.
0 Converter Assembly - Hub or seam weld leak.
- Oil overfill.
- Engine coolant in transmissio
0 Oil Pump Assembly
Rear Extension
- Damaged extension to case seal.
Figure
6 Diagnosis Chart A

HYDRAULIC DIAGNOSIS 700-R4-9
A OILPAN G OIL PUMP SEAL ASSEMBLY L MANUAL SHAFT SEAL
B CASE
H OIL PUMP TO CASE SEAL M GOVERNOR COVER
C COOLER CONNECTORS
& 1 CONVERTER
N SPEEDOSEAL
PLUGS J VENT 0 EXTENSION TO CASE SEAL
D T.V. CABLE SEAL
K ELECTRICAL CONNECTOR P EXTENSION OIL SEAL
E SERVO COVER SEAL ASSEMBLY
F OIL FILL TUBE SEAL
Figure
7 Possible Leak Points

100.R4.10 HYDRAULIC DIAGNOSIS
(Verify With Gage-Check - Rotor guide omitted or misassembled.
Oil Level
81 Engine Tune.) - Rotor cracked or broken. - T.V. valve, reverse boost valve or bushing
stuck, damaged or incorrectly assembled.
- Orifice hole in pressure regulator valve
- Sticking slide or excessive rotor clearance.
- Pressure relief ball not seated or damaged.
- Porosity in pump cover or body.
- Wrong pump cover.
- Pump faces not flat.
- Excessive rotor clearance.
- Intake pipe restricted by casting flash.
- Cracks in filter body or intake pipe.
- "0" ring seal missing, cut or damaged.
- Wrong grease used on rebuild.
T.V. Exhaust Ball
- Stuck or damaged.
* Throttle Link - Misassembled, binding or damaged.
- Manual valve scored or damaged.
- Spacer plate or gaskets incorrect, mis-
assembled or damaged.
- Face not flat.
- Throttle valve sticking.
- T.V. limit valve sticking.
- Modulated downshift valve stuck.
- Line bias valve stuck.
- 2-3 Shift valve stuck.
- Check balls omitted or misassembled.
- Case to valve body face not flat.
T.V. Exhaust Ball
- Stuck or damaged.
Throttle Lever
81 Bracket - Misassembled, binding or damaged.
Figure
8 Diagnosis Chart B

HYDRAULIC DIAGNOSIS 700-R4-I 1
CONDITION I INSPECT COMPONENT
HIGH OR LOW SHIFT
POINTS (Continued) 0 Oil Pump Assembly
0 Valve Body Assembly
Case
Valve Body
- Stuck pressure regulator valve or T.V.
boost valve.
- Sticking pump slide.
- Sticking throttle valve or plunger.
- Modulated T.V. up or down valves
sticking.
- T.V. limit valve sticking. - Spacer plate or gaskets misassembled,
damaged or incorrect.
I - Line bias valve sticking.
- Porous or damaged valve body pad.
- Governor screen restricted or damaged.
- 2-4 Servo
a. 2-4 accumulator porosity.
b. Damaged servo piston seals.
c. Apply pin damaged or improper length.
- 2-4 Band assembly
a. Burned.
b. Anchor pin not engaged.
- Governor valve sticking. - Governor driven gear loose or damaged:
a. Wear on bottom of gear indicates pin
is not pressed in deep enough.
b. Wear of corner of gear indicates pin
is missing.
c. Wear resembles an apple core if wrong
gear is used, or there is a burr on the
output shaft.
d. Wear on one side of gear indicates out-
put shaft snap ring is missing or the
governor has seized in the bore.
- Governor driven gear retaining pin missing.
- Nicks or burrs on output shaft.
- Nicks or burrs on governor sleeve or case
bore.
- Governor support pin in case too long or
short.
- Governor weights or springs missing,
binding or damaged.
- 1-2 Shift valve sticking. - Spacer plate or gaskets mispositioned or
damaged.
- Case to valve body face not flat or dam-
aged.
- Governor screen restricted or damaged.
Figure 9 Diagnosis Chart C