Patent ID: 8864537

Claim:
A gear case assembly for a marine propulsion system comprising: a gear case having a first end and a second end, the first end being adapted to connect the gear case to a remainder of the marine propulsion system, the second end being disposed opposite the first end; a driveshaft disposed at least in part in the gear case, the driveshaft having a driveshaft axis; a propeller shaft operatively connected to an end of the driveshaft, the propeller shaft being disposed at an angle to the driveshaft; a transmission chamber defined in the gear case, the end of the driveshaft and at least a portion of the propeller shaft being disposed in the transmission chamber; a driveshaft passage fluidly connected to the transmission chamber, the driveshaft passage housing at least a portion of the driveshaft, the driveshaft passage being disposed between the first end of the gear case and the transmission chamber in a direction parallel to the driveshaft axis; a lubricant return passage fluidly connected to the transmission chamber and the driveshaft passage, the lubricant return passage being disposed between the first end of the gear case and the transmission chamber in a direction parallel to the driveshaft axis; a pump driven by the driveshaft, during operation of the driveshaft: the pump pumps lubricant from the transmission chamber to the driveshaft passage, and from the driveshaft passage, the lubricant flows through the lubricant return passage and back to the transmission chamber; a first lubricant filling port for fluidly communicating one of the lubricant return passage and the driveshaft passage with an exterior of the gear case, the first lubricant filling port defining an aperture in the one of the lubricant return passage and the driveshaft passage; a first plug selectively disposed in the first lubricant filling port; a second lubricant filling port for fluidly communicating one of the lubricant return passage and the transmission chamber with the exterior of the gear case, the second lubricant filling port defining an aperture in the one of the lubricant return passage and the transmission chamber, the second lubricant filling port being closer to the second end of the gear case than the first lubricant filling port in the direction parallel to the driveshaft; a second plug selectively disposed in the second lubricant filling port; and a check valve disposed in the lubricant return passage between the first and second lubricant filling ports in the direction parallel to the driveshaft axis, the check valve permitting lubricant to flow through the check valve toward the transmission chamber, the check valve preventing lubricant to flow through the check valve away from the transmission chamber.