Most Likely Culprits:
* Wheel Bearing: A worn or damaged wheel bearing is a very common cause of whining sounds that increase with speed, often accompanied by a grinding noise if the bearing is severely damaged. The noise is usually more pronounced when turning. This is the most probable cause given your description.
* Differential: Problems within the rear differential can also cause whining noises, especially under load or when turning. Grinding could indicate worn gears or other internal damage. This is less likely if the noise is primarily localized to the right rear wheel.
* Brake System: While less likely to cause a *whining* sound primarily, severely worn or damaged brake components (particularly the caliper or pads) *could* contribute to grinding. However, a brake problem usually presents with other symptoms, such as pulling to one side during braking or a spongy brake pedal.
What to do:
1. Safety First: Don't drive the truck extensively with this problem. A severely damaged wheel bearing can fail completely, leading to loss of control.
2. Visual Inspection: Carefully inspect the right rear wheel and tire. Look for anything obvious, like loose wheel nuts, damage to the tire, or brake components rubbing against the rotor or wheel.
3. Jack Up the Truck: Safely jack up the right rear of the truck and secure it on jack stands. Try to rotate the wheel by hand. If you feel significant roughness, resistance, or play in the wheel bearing, it's likely the culprit. Listen closely for the whining sound as you rotate the wheel.
4. Professional Diagnosis: Unless you are experienced with automotive repair, it's best to take your S10 to a qualified mechanic for a proper diagnosis. They have the tools and expertise to accurately pinpoint the problem and perform the necessary repairs. Describing the sound and the grinding noise will help them.
Important Note: Ignoring this problem could lead to more serious and expensive damage. Get it checked out as soon as possible.
