Lower Unit Gearcase Failure: Rebuild or Replace?

Fishing line has a habit of finding its way around a propeller shaft and destroying prop shaft seals. There are two seals - one for vacuum and one for pressure. When either is damaged, water enters the gearcase. As the gearcase warms. oil exits under resulting pressure. The gearcase then refills with water when a vacuum forms as the submerged gearcase cools rapidly. Bearing failure follows due to lack of lubrication.   

Lack of gearcase lubrication will cause a bearing to sieze almost instantly which, in this case, also caused the driveshaft from the powerhead to shear. The powerhead continued running when the grearcase stopped, producing a large amount of metal shavings that accumulated in the gearcase. The best repair option would normally be a new driveshaft but due to excessive metal damage we need a complete lower unit replacement – new housing, gears, shaft, and bearings.  

Whether to opt for a new or rebuilt gearcase depends on who performs the rebuild and whether the repair is covered by insurance. We historically go with the complete new gearcase option as pricing for gearcases has become more reasonable than in the past. Selecting a re-manufactured or factory replacement unit comes down to which provides the better value and warranty for the owner.  Always compare the options carefully.

Enjoy the excellent winter fishing while the crowds are at Grandma’s house.

Chris Mapp
Coastal Bend Marine | Port O’Connor, TX
361-983-4841 | coastalbendmarine.com