I developed a whining noise on my 94 mercruiser alpha 1stern drive this morning. It sounds like a cross between a whine and a grinding sound. It only makes the noise when the boat is in gear. The tilt gauge recently quit working but the stern drive appears to still work fine. Not sure if that is relevant info or not. I'm going to check the stern drive fluid this afternoon but not sure what to check next. All other fluids are good. Could this noise be coming from a valve or possibly a water pump. Any insight would be helpful.