Re: grease Home › Forum › Ask A Member › grease › Re: grease MumblesReplies: 5762Topics: 298 July 16, 2018 at 2:11 pm #79644 You don’t use grease in those gearcases. They take 80W-90 or 90 weight marine grade gear oil meant for outboard motors. Grease was usually used in older direct drive gearcases.