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Home >> Chevrolet >> 1999 >> Metro L4-079 1.3L VIN 2 MFI >> Repair and Diagnosis >> Transmission and Drivetrain >> Automatic Transmission/Transaxle >> Testing and Inspection >> Initial Inspection and Diagnostic Overview >> Road Test Procedure

Road Test Procedure

Refer to Road Test Caution in Service Precautions.

Important:
^ Perform the road test following the sequence given.
^ Km/h (mph) shift points will vary with actual throttle position and driver habits.
^ Compare the results of the road test with the Transaxle Shift Speed Schedule. Use these results with the diagnosis information for the transaxle evaluation.
^ This test should only be performed when traffic and road conditions permit.
^ Observe all traffic and safety regulations.

Drive and Reverse Engagement Test
1. Turn the ignition switch to ON.
2. Depress the brake pedal fully.
3. Place the manual selector in the Park (P) range.
4. Start the engine.
5. Move the manual selector from the Park (P) range to the Reverse (R) range.
6. Observe the reverse engagement.
7. Move the manual selector from the Reverse (R) range to the Drive (D) range.
8. Observe the drive engagement.
9. Move the manual selector from the Drive (D) range to the Park (P) range.
10. Turn the ignition switch to the LOCK position.
11. Verify that the following conditions exist:
- The reverse engagement takes approximately 1.4 seconds at the normal operating fluid temperature.
Normal operating fluid temperature is 70 - 80°C (158 - 176°F).
- The drive engagement from the reverse engagement takes approximately 1.0 seconds.
- The reverse and the drive engagements should be immediate, but not harsh.
If the reverse and the drive engagements are slow to engage or seem too harsh, refer to Line Pressure Test. Line Pressure Test

Upshifts Test
1. Move the manual selector to the Drive (D) range.
2. Accelerate the vehicle using steadily increasing throttle pressure.
3. Note the vehicle speeds and the shift points for the following gears:
^ Second gear
^ Third gear
Use the following steps in order to perform the part throttle downshift test:

Important: Perform all of the road test procedures only after the fluid has reached the normal operating temperature of 70 - 80°C (158 - 176°F).

1. Operate the vehicle at the speeds of 35 - 45 km/h (22 - 28 mph).
2. Verify that the manual selector is in the Drive (D) range.
3. Quickly press the accelerator pedal to approximately half throttle.
4. Verify that the transaxle immediately downshifts to second gear.

Full Throttle Downshift Test
1. Operate the vehicle at the speeds of 77 - 88 km/h (48 - 55 mph).
2. Verify that the manual selector is in the Drive (D) range.
3. Quickly press the accelerator pedal to the Wide Open Throttle (WOT) position.
4. Verify that the transaxle immediately downshifts to second gear.

Manual Downshift Test
1. Move the manual selector to the Drive (D) selector.
2. Operate the vehicle at 40 km/h (25 mph).
3. Release the accelerator pedal.
4. Move the manual selector to the Low (L) range.
5. Verify the following operating conditions:
^ The transaxle downshifts immediately to first gear.
^ The engine reduces the vehicles speed.

Coastdown Downshift Test
1. Verify the manual selector is in the Drive (D) position.
2. Depress the accelerator pedal until the transaxle is in third gear.
3. Release the accelerator pedal.
4. Lightly apply the brake pedal.
5. Observe the vehicle speeds at points of downshifts.

Manual Third (D) Gear Range Selection Test
1. Stop the vehicle.
2. Move the manual selector to the Drive (D) range.
3. Slowly accelerate the vehicle and verify the following operating conditions:
^ The transaxle upshifts from the first to the second gear.
^ The transaxle upshifts from the second to the third gear.

Manual Second (2) Range
1. Stop the vehicle.
2. Place the manual selector in the second (2) range.
3. Slowly accelerate the vehicle.
4. Verify that the transaxle upshifts from the first to the second gear.
5. Accelerate to 40 km/h (25 mph).
6. Verify that the transaxle does not upshift from second to third gear.

Manual Low Test
1. Stop the vehicle.
2. Place the manual selector in the Low (L) range.
3. Slowly accelerate the vehicle.
4. Verify that the transaxle does not upshift from the first to the second gear.

Reverse (R) Test
1. Stop the vehicle.
2. Place the manual selector in the Reverse (R) range.
3. Slowly accelerate the vehicle.
4. Verify that the vehicle operates in a rearward direction.





Transaxle Shift Speed Schedule
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