Automatic Transmission: NVH Saab 9-5 II

Noise and Vibration Analysis

A noise or vibration that is noticeable when the vehicle is in motion MAY NOT be the result of the transmission. Refer to the SYMPTOMS - VIBRATION DIAGNOSIS AND CORRECTION procedure.

If noise or vibration is noticeable in PARK and NEUTRAL with the engine at idle, but is less noticeable as RPM increases, the vibration may be a result of poor engine performance.

1. Vibration may also be caused by a small amount of water inside the converter.
2. Inspect the shift control cable mounting.
3. Inspect the engine and transmission mounts for damage and loose bolts.
4. Inspect the transmission case mounting holes for the following conditions: Missing bolts, nuts, and studs Stripped threads Cracks
5. Inspect the flywheel for the following conditions: Missing or loose bolts Cracks Imbalance
6. If the noise or vibration is noticeable in PARK and NEUTRAL with the engine at idle, but is more noticeable as RPM increases, the vibration may be an engine imbalance or a transmission imbalance.

Noise

Note. Do not confuse this noise with pump whine noise, which is usually noticeable in PARK, NEUTRAL and all other gear ranges. Pump whine will vary with line pressure.

You may notice a whining noise from the torque converter when the vehicle has stopped and the selector lever is in DRIVE or REVERSE. The noise increases when engine speed increases. The noise disappears when the vehicle is in motion or when the torque converter clutch is activated because both clutch halves spin at the same speed.

Perform a stall test to make sure the noise is actually coming from the converter

1. Place your foot on the brake.
2. Put the gear selector in DRIVE.
3. Depress the accelerator to approximately 1, 200 RPM for no more than 6 seconds.

A torque converter noise will increase under this load.