Whine Noise From Engine Area On Deceleration - keywords accelerate belt clutch decelerate generator noise pulley slip SS whine whistle

This PI was superseded to update model years. Please discard PIT3775.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

A whirring/whine noise may be noticed during full throttle acceleration after a transmission shift or after a sudden release of the throttle at high RPM. This is most likely the generator over run clutch. This is a one way type of clutch that allows the generator rotor to run at a higher RPM prior to a transmission shift between gears. It also allows the generators rotor to slowly ramp down instead of a sudden change in RPM when the throttle is released. A sudden RPM change could lead to a belt slip noise. This may sound similar to a supercharger whine noise.

This is a normal operating characteristic and no repairs are to be performed. Compare to a like vehicle if necessary.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.