2006 Pontiac Torrent Whistling Sound

My Pontiac Torrent makes a whistling noise when moving over 15 mph. It doesn’t always do it, but it does most of the time. I’ve had the tires rotated and balanced, the brakes checked, … Someone told me it was the carrier bearing in the rear. My question: What is the carrier bearing and could that be the cause? I’m stumped.

A few questions to help clarify the situation. Is this Torrent an All Wheel Drive vehicle? Does the sound appear to be coming from the front or back? If you cannot determine as the driver, have someone move around in the vehicle while the sound is present to zero in on the sound. Is there a specific maneuver that elicits the sound, i.e. right turn, left turn, straight ahead, driving on slick surfaces, following a hard acceleration, etc.? What has the dealer said about the noise? Have you ridden in a similar Torrent to see if the sound is present in that one?

Answers will help us help you.

The Torrent is All Wheel Drive. We can’t seem to pinpoint exactly where the sound is coming from, but it only starts when going 15-20 mph and is unaffected by steering, braking, road surface conditions, accelerations, … We’ve tried rolling down different windows and listening, but just can’t seem to locate it. My wife is sure it’s in the front, but my son and daughter-in-law think it’s in the rear. And it doesn’t always whistle, just most of the time. We haven’t gone to a dealer yet, but are considering it. We haven’t ridden in another Torrent. We thought maybe it was the luggage rack, but making changes in the position of the cross bars has no effect. ???

If it is a whistling noise and isn’t always present, it doesn’t sound like a bearing to me. I wonder if it isn’t a wind noise. I had a 1965 Rambler that had a whistling noise. It would start at 45 miles per hour and go away at 60. I didn’t worry about it, but the service manager heard the noise and traced it down to the grille and repaired it under warranty. I didn’t ask to have it fixed and sort of missed the noise when it was gone. I also had a rental car that had a terrible buzzing noise, but this was so bad that I returned the car. I was given a free upgrade the the agent told me that the windshield in the original rental had been replaced and not sealed properly. I suppose an improperly sealed windshield could also cause a whistling noise.

Another question – can you make the whistle come and go by accelerating and deaccelerating while holding constant speed? On a slight descending roadway, accelerate up to a speed; then float the throttle while coasting; and then lift the throttle completely. Does the sound change in loudness or character?

To answer your original question, a carrier bearing supports the differential (front or rear) and bears the load generated by the pinion gear. Carrier bearings usually make roaring noise that come and go with the engine load placed on that axle. Load is not placed on the rear differential and transfer case gears until the front wheels are turning at a different rate than the rears. Whistles and whines are usually caused by mesh errors of the ring and pinion gears.

If the whistle is unchanged by the load placed on the engine, it is unlikely to be caused by running gear i.e front differential, transfer case, drive shaft, rear differential, or AWD power transfer unit in the rear.

If the sound is definitely speed related I would follow Triedaq’a advice and look for an acoustic whistle.

I have another thought: if the frequency of the whistle is relatively constant, I wonder if you have a vacuum leak. I don’t know if the heater and air conditioning controls on your Pontiac are operated by vacuum, but when the car starts whisling, try turning off the heating and air conditioning systems. If it goes away, you know where the problem is.