Our Envoy has started to make a whirring noise when we accelerate. What could be causing this?

The vehicle has to be moving for the noise to happen. It's drive train related because the noise does not mimic the RPM of the engine. It sounds like it could be coming out of the rear axle but not sure.

This noise is most likely a bearing issue, so we need to start by trying to verify what type of bearing it is.

Here is a guide that will get us started:

https://www.2carpros.com/articles/whirring-sound

If the noise is only there when you are moving, does the noise get louder when you drive faster? If it does then this is a tire or a bearing.

If the noise gets quieter when you swerve from side-to-side loading and unloading the suspension, then that is a bearing noise.

The side that you are putting the weight of the vehicle on when turning is the side that has the bearing issue. If it sounds like it is coming from the rear, then this would be the rear wheel bearing.

If none of this causes any difference, then we need to accelerate to get the noise to be there and then coast and find out if the noise goes away or changes. This would point to a pinion bearing issue.

To confirm this, we need to remove the rear driveshaft and drive in 4WD high to see if the noise is gone.

https://www.2carpros.com/articles/car-howling-noise

https://www.2carpros.com/articles/how-to-remove-a-drive-shaft

Please run through all this info and let me know what you find. Thanks