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Automatic Transaxle Diagnosis - 4T40-E & 4T45-E: NVH Pontiac Sunfire I

Automatic Trans ~146 words

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 torque converter whine when the vehicle is stopped and the transaxle is in Drive or Reverse. This noise will increase as you increase the engine RPM. The noise will stop when the vehicle is moving or when you apply the torque converter clutch, because both halves of the converter are turning 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 1200 RPM for no more than 6 seconds.

A torque converter noise will increase under this load.

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