Free - Twin Disc MG-521 Troubleshooting Guide Twin Disc MG 521 Marine Transmission Parts - Gasket Set Section Loading... 1 Twin Disc Gasket and seal kit for marine gear MG521 . Price: $ 1,420.21 Qty: ^ Details In Stock Add to Cart 2 Rubber Block for Twin Disc Marine Gears . Price: $ 17.92 Qty: ^ Details In Stock Add to Cart 3 Mechanical & Electric Gauges See Our Gauges Page 4 Controls Cables & More... See All Control, Cables & More 5 Marine Water Pumps See All Marine Water Pumps 6 Fresh Water Pumps See All Fresh Water Pumps Free - Twin Disc MG-521 Troubleshooting Guide