Free - Twin Disc MG-509 Troubleshooting Guide Twin Disc MG 509 Marine Transmission Parts - Seal Section Loading... 1 Front seal for MG509 and rear seal for MG507 M137 Input shaft seal for MG509 Output shaft seal for MG507 Price: $ 63.70 Qty: ^ Details In Stock Add to Cart 2 Rear seal for Twin Disc MG509 ratio 1.45 to 3.84 M2371 Output shaft seal Price: $ 49.61 Qty: ^ Pictures In Stock Add to Cart 3 Rear Seal for Twin Disc MG509 - Ratio 3.83 to 4.95 M136A Important: The transmission uses 2 of this seal Price: $ 29.84 Qty: ^ Details In Stock Add to Cart 4 Mechanical Gauges Standard Mechanical Gauges with Alarm Electrical Gauges 12 Volts Electrical Gauges 24 Volts 5 Controls Cables & More... See All Control, Cables & More 6 Marine Water Pumps Detroit Diesel Cummins Caterpillar John Deere See All... 7 Engine Water Pumps Detroit Diesel Cummins Caterpillar John Deere Free - Twin Disc MG-509 Troubleshooting Guide