GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Geo 🢒 1997 🢒 Prizm 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 3 Speed-MB3 🢒 Road Test

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 in this section 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:
    12. • The reverse engagement takes approximately 1.4 seconds at the normal operating fluid temperature.
    • Normal operating fluid temperature is 50-80°C (122-176°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

Upshift 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:
    4. • Second gear (2)
    • Third gear (3)

Part Throttle Downshift Test

Important: Perform all of the road test procedures only after the fluid has reached the normal operating temperature of 50-80°C (122-176°F).

  1. Operate the vehicle at the speeds of 64-88 km/h (40-55 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 64-88 km/h (40-55 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 the speeds of 64-88 km/h (40-55 mph).
  3. Release the accelerator pedal.
  4. Move the manual selector to the Second Gear (2) range.
  5. Verify the following operating conditions:
    6. • The transaxle downshifts immediately to second gear.
    • The engine reduces the vehicle 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:
    4. • The transaxle upshifts from the first gear to the second gear.
    • The transaxle upshifts from the second gear 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 gear to the second gear.
  5. Accelerate to 40 km/h (25 mph).
  6. Verify that the transaxle does not upshift from the second gear to the 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 gear 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.

Park/Neutral Position (PNP) Switch

The Park/Neutral Position (PNP) Switch is located next to the solenoid wire harness and is controlled by the shift select cable. The PNP switch sends a signal to the Powertrain Control Module when the manual selector is in P,R,N,2 and L. The PCM uses signals to determine which gear has been selected and to determine shift points and the Torque Converter Clutch (TCC) engagement.

Vehicle Speed Sensor (VSS)

The Vehicle Speed Sensor (VSS) is located above the differential on the transaxle. The VSS driven gear is driven by the speedometer drive gear on the differential and sends a speed signal to the speedometer. The speedometer converts this vehicle speed signal and provides the Powertrain Control Module (PCM) with a speed signal. The PCM uses the VSS input to determine the shift points and the Torque Converter Clutch (TCC) engagement. If a fault is present in the VSS circuit, the PCM will provide minimum driveability shift points and the TCC apply schedule until the VSS circuit can be repaired.