If your vehicle is showing high-pitched humming noise that gets louder as vehicle speed increases, here are the most likely causes and the parts you'll need to fix each one.
The bearings that allow your wheels to spin smoothly wear out over time. When failing, they create a humming or groaning noise that scales directly with vehicle speed.
Tires that have worn unevenly due to a lack of rotation, poor alignment, or worn suspension components can produce a rhythmic, high-pitched hum that mimics a bad wheel bearing.
The gears in your axles require proper lubrication. Low fluid or worn internal bearings will cause a high-pitched whine or hum from the front or rear of the vehicle that changes depending on whether you are accelerating or coasting.
Rear-wheel or all-wheel drive vehicles often have a bearing supporting the middle of the driveshaft. As the rubber degrades or the bearing dries out, it emits a high-pitched hum or whine from underneath the center console.
A recently replaced windshield or loose exterior trim can catch the wind at higher speeds, creating a high-pitched aerodynamic hum or whistle that sounds mechanical but is actually wind noise.
Bearings inside the transmission or transfer case can fail, causing a high-pitched whine that increases with vehicle speed regardless of engine RPM or what gear you are in.