What would cause honda ridgeline whining noise?

Your Honda Ridgeline's whining noise can be caused by a few different things, largely dependent on the location of the whine. While wheel bearing noise is typically described as "whistling", I could Make the jump and say this is what you may be describing. Alternatively, you may be looking at low transmission fluid, a failed throw out bearing, a worn throw out bearing, or a bad input shaft bearing. Low transmission fluid is both the simplest to diagnose and the simplest to fix, so it's probably where you should begin. Top off as necessary. If this doesn't seem to fix your issue, you'll need to try to localize the sound. In the case of a bad wheel bearing, it's often possible to "test" by trying to shake the wheel back and forth.