Pontiac Fiero 1988 Service Manual page 846

5 SPEED ISUZU MANUAL TRANSAXLE 7B2A-1
SECTION 7B2A
5-SPEED ISUZU MANUAL TRANSAXLE
RPO' S MK7 AND MT2
CONTENT
Diagnosis
7B2A-1 Shaft Reassembly.......... . . . . . . . . 7B2A-9
Unit Repair
7B2A-3 Differential Case Assembly 7B2A-10
Case Disassembly 7B2A-3 Transaxle Assembly 7B2A-10
Shaft Disassembly 7B2A-7
Specifications
7B2A-15
Differential Case Disassembly . . . . . . . . 7B2A-8
Special Tools
7B2A-16
Cleaning and Inspection 7B2A-8
DIAGNOSIS
Figure 1
Before attempting to repair the clutch, transaxle
or related linkages for any reason other than an
obvious failure, the problem and probable cause
should be identified. A large percentage of clutch and
manual transaxle problems are manifested by shifting
difficulties such as high shift effort, gear clash and
grinding or blockout. When any of these problems
occur, a careful analysis of these difficulties should be
accomplished, and the following checks and adjust-
ments made before disassembling the clutch or trans-
axle for repairs.
Diagnosis of drivetrain noises may seem baf-
fling because many noises believed to be coming from
the transaxle may actually be originating from other
sources, such as tires, road surfaces, wheel bearings,
engine, and exhaust system.
These noises may vary by car size, type and
amount of body insulation used. Therefore, a thor-
ough and careful check should be made to determine
the source of the noise before disassembling the trans-
axle. Noise which originates in other places cannot be
corrected by adjustment or replacement of parts in the
transaxle.
It should also be remembered that transaxle
gears, like any mechanical device, are not absolutely
quiet and, will exhibit some normal operating noise.
The following is a suggested approach to verify
suspected transaxle noises.
1. Select a smooth, level asphalt road to reduce tire
and resonant body noise.
2. Drive car far enough to thoroughly warm up all
lubricants.
3. Note speed at which noise occurs, and, in which
gear range the transaxle is in at the time.
4. Check for noises with engine running and car
stopped.
5. Determine in which of the following drive con-
ditions noise is occurring:
A. Drive - light acceleration or heavy pull.
B. Float - maintaining constant car speed at
light throttle on a level road.
C. Coast - partly or fully closed throttle
with transaxle in gear.
D. All of above.
6. After road testing the car, refer to the following
conditions and probable causes along with the
Diagnosis Chart.
Bearings
Bad bearings generally produce a rough "growl"
or "grating" sound, rather than the "whine" which is
typical of gear noise.
Before diagnosing a bearing problem, clean the
cone assembly thoroughly in solvent and allow to dry
completely.
Whenever a bearing is removed, a careful
inspection must be made to determine the cause of the
problem and whether any related parts have been
damaged.
If bearing has become magnetized, removal of
metal particles from inside cage cannot be accom-
plished unless bearing is demagnetized.
Bearings fail by lapping, spalling or locking.