Wheel Bearing: A faulty wheel bearing can cause a humming noise that increases with speed and changes pitch when turning. Check for any play or roughness in the wheel bearings by jacking up the car and spinning the wheels by hand.
CV Joint: A worn or damaged CV (constant velocity) joint can also produce a humming noise, especially when turning. CV joint issues are more likely to cause noise when the steering wheel is turned sharply or when accelerating from a stop. Inspect the CV boots for tears or cracks, and look for any signs of grease leaking out.
Driveshaft: A faulty driveshaft can cause a variety of noises, including a humming sound. Check the driveshaft for any loose or damaged components, and make sure that the U-joints are in good condition.
Transmission: In some cases, a humming noise can be caused by a problem with the transmission. This is less likely in a 1996 Contour, but it's worth considering if the noise is accompanied by other symptoms such as slipping gears or difficulty shifting.
Tire Noise: Uneven tire wear or damaged tires can also cause humming or rumbling noises. Make sure that your tires are properly inflated and have even tread wear.
If you're not comfortable inspecting and diagnosing the problem yourself, it's best to take your car to a qualified mechanic for an accurate diagnosis and repair.
