Diagnosis; Preliminary Checking Procedure; Road Test Procedure - Pontiac Fiero 1988 Service Manual

7A1-2 ON-VEHICLE SERVICE
DIAGNOSIS
Automatic transaxle malfunctions are caused by
one, or a combination, of the following:
• Improper fluid level
• Low engine performance
• T.V. cable misadjustment
• Manual linkage misadjustment
• Internal fluid leaks
• Electrical failure(s)
• Mechanical failure
PRELIMINARY CHECKING PROCEDURE
Most automatic transaxle problems are caused
by improper external adjustments. Before servicing a
transaxle, the fluid level and external adjustments
should be checked and corrected as necessary.
Inspect
Warm up engine and transmission to operating
temperature.
Fluid level. Refer to "Fluid Level Checking Pro-
cedure", Figure 1.
Engine idle speed.
4.
5.
6.
Important
• Do not attempt to proceed with the Pre-
liminary Checking Procedure if the engine
does not perform properly. Correct any
engine malfunction first.
T.V. cable for freedom of movement and
returnability at cable activating lever. Check to
be sure that the T.V. cable is adjusted to the
proper length.
Shift control linkage. Make sure the linkage
does not bind and is properly adjusted.
Test drive car.
N O R M A L
F I L L UP
C H E C K F O R E X T E R -
N A L L E A K S AND F O R
E F E C T I V E V A C U U M
M O D U L A T O R
D R A I N & R E F I L L
C H E C K F O R W A T E R
IN F L U I D OR HIGH
F L U I D L E V E L
D R A I N E X C E S S F L U I D
- C H E C K F O R C O O L A N T
C O N T A M I N A T I O N
M A K E F U N C T I O N A L
C H E C K & C H E C K
F O R C O O L A N T OR
B U R N E D C L U T C H E S
C H E C K T V C A B L E
& M A N U A L L I N K A G E
A D J U S T M E N T
P E R F O R M R O A D
T E S T . R E F E R T O
D I A G N O S T I C
C H A R T S AND
P R E S S U R E T E S T S
G20027-7A
Figure 1 Preliminary Checking Procedure
ROAD T E S T PROCEDURE
Important
• Perform the road test in an organized
manner. Carry out all steps in the
sequence shown. Note the results of each
step for later evaluation with the aid of
Diagnostic Charts in the Hydraulic Diag-
nosis and Unit Repair Section.
"DRIVE" range
a. Place gear selector into "Drive" (D) and
accelerate car.
b. Observe the 1-2 and 2-3 shift. Shift points
will vary with throttle position.
c. Observe Torque Converter Clutch (TCC)
engagement. This should occur between
35-50 mph (57-80 km/h). Refer to
Hydraulic Diagnosis.
Important
• TCC will not engage if the engine is
not at operating temperature.
d. Observe 3-2 downshift.
o Part Throttle Downshift
— At a speed of 25-30 mph (40-50
km/h) quickly open throttle approx-
imately 3/4.
o Full Throttle Downshift
— At a speed of 50 mph (80 km/h)
open throttle fully.
"INTERMEDIATE" range (1 or 2) — 3rd gear
is inoperative.
a. Place gear selector into "2".
b. Accelerate car and observe 1-2 shift. The
shift point will vary with the throttle open-
ing. The 1-2 shift will be firmer than in
the "D" range.