Operation CHARM: Car repair manuals for everyone.

Noise Conditions

Drive Link Noise: A whine or growl that increases or fades with engine RPM. This noise is most noticeable under a light throttle acceleration, or in Park or Neutral with the car stationary.

Final Drive Nose: A hum related to car speed. This noise is most noticeable under a light throttle acceleration or zero throttle coastdown.

Planetary Gear Noise: A whine related to car speed. This noise is most noticeable in First gear, Second gear, Fourth gear, or Reverse. The condition becomes less noticeable after an upshift.

Pump Noise: A high pitched whine that increases with engine RPM and may be affected by modulated line pressure boost.

Torque Converter: A whine usually noticed when a vehicle is stopped and the transmission is in DRIVE or REVERSE. The noise will increase with the engine RPM. Refer to Torque Converter Evaluation for further information.