SEAL AS 8E9650 - Caterpillar

Operation
The marine gear is attached directly to the engine flywheel housing. Full power is transferred from the engine through the marine gear in either a forward or reverse rotation at a reduced speed to the propeller shaft.Back to back, hydraulically actuated clutches operate the forward and reverse drives. A selector valve directs the flow of oil to either of the clutches for forward or reverse operation. The valve is operated by a lever which can be manually or remotely controlled.A gear type oil pump, mounted on the rear of the marine gear, provides oil pressure to actuate the clutches, and also, the oil to lubricate the bearings in the marine gear.The clutch front section engages the three gear drive section and rotates the propeller shaft in the same direction of rotation as the engine. The clutch rear section engages the two gear drive section and reverses the direction of propeller shaft rotation.The direction of flywheel rotation for a standard engine is counterclockwise, when viewed from the flywheel end of the engine. With a right hand propeller, the clutch rear section is engaged to produce ahead motion.
COUNTERCLOCKWISE ROTATING FLYWHEEL WITH CLUTCH REAR SECTION ENGAGED
1-Clutch rear section. 2-Clutch front section.
CLOCKWISE ROTATING FLYWHEEL WITH CLUTCH REAR SECTION ENGAGED
1-Clutch rear section. 2-Clutch front section.In twin engine installations a standard engine (counterclockwise flywheel rotation) and an engine option which provides clockwise flywheel rotation is desirable. The standard engine propeller should be a right hand propeller and the other engine propeller should be a left hand propeller. This type of engine installation allows the clutch rear section to engage the two gear drive, in each marine gear and produce ahead motion from both engines.Hydraulic System
In the following information the clutch rear section will be referred to as the "ahead clutch" and the clutch front section will be referred to as the "astern clutch".
HYDRAULIC OIL TO ENGAGE AHEAD CLUTCH
1-Manifold. 2-Selector valve. 3-Passage. 4-Clutch spider. 5-Passage. 6-Clutch cylinder. 7-Passage through driving ring. 8-Cavity. 9-Ahead clutch plates. 10-Ahead clutch piston. 11-Dump piston.When selector valve (2) is moved to engage ahead drive clutch plates (9), high pressure oil flows from manifold (1) through passage (3) around the tube in the center of the oil pump drive shaft.
AHEAD CLUTCH DRIVE SCHEMATICOil through passage (5) in clutch spider (4) is directed through passage (7) in the clutch driving ring and into clutch cylinder (6). High pressure oil moves dump valve piston (11) toward the center of the cylinder where the piston blocks the dump valve oil exit. High pressure oil enters clutch cylinder cavity (8) behind the ahead clutch piston (10), and moves the piston to engage the ahead clutch.The two cutaway illustrations show oil flow through the dump valve. Clutch disengagement occurs when the actuating oil pressure is cut off from the dump valve piston by action of the selector valve. The dump valve piston moves outward by centrifugal force aligning dump passage (15) in the piston with the passage to clutch cavity (14). Oil which was behind the