Roof vent in Garage

Hello, I'm a new home owner and new to the forum. I'm not sure where to post this so move it if im In the wrong place. I've got a 2 stall garage attached with a roof vent. Heavy rain and snow with wind the roof vent leaks into my garage. Are roof vents in a garage really needed? I thought about throwing some insulation up there to at least cut the wind from blowing snow. What's the best way to weather proof a roof vent? I plan to finish it with drywall so I need to do something to cut the weather. Thanks