CHAIN 8X9874 - Caterpillar

Illustration 1 g03715707
Left Propel Motor (1) Flushing relief valve (2) Port "L1" (3) Port "A" (4) Port "B" (5) Speed sensor (6) Final driveNote: The above illustration shows the left propel motor. The right propel motor is identical except for orientation. The right motor is rotated so the system ports are located on the top face.Each propel motor is a piston-type motor. Each motor drives a rear wheel through two-speed planetary final drive (6). The ports on the motors are marked for identification. On the left motor, port "A" (3) is the reverse port, and port "B" (4) is the forward port. On the right motor, port "A" is the forward port, and port "B" is the reverse port. Port "L1" (2) is the case drain port on the left motor. Port "L2", located on the opposite side of the motor from port "L1", is the case drain port on the right motor. Each motor is equipped with dual-signal speed sensor (5). A gear on the output shaft of the motor rotates past the tip of the speed sensor. Each time a tooth passes the sensor, an electrical impulse is sent to the transmission ECM. These impulses are out of phase with one another. The transmission ECM converts the frequency of the impulses to a vehicle speed and the phase of the impulses into a travel direction. Each propel motor contains a flushing valve. Flushing valves direct oil from the low-pressure side of the propel loop to flushing relief valve (1). The flushing relief valves open when the pressure in the low-pressure side of the propel loop is greater than the flushing relief pressure setting. Each flushing relief valve directs a metered amount of oil from the low-pressure side of the loop into the motor case drain. The case drain line on each motor directs oil from the motor cases to the cooler bypass manifold.
Illustration 2 g03715710
Propel Motor Cross Section (1) Flushing relief valve (7) Cylinder block (8) Piston (9) Slipper feet (10) Flushing spool (11) Valve plate (12) Swashplate (13) Output shaftThe right propel motor and left propel motor are identical. Each propel motor is a piston-type motor with a fixed displacement. The motor contains flushing relief valve (1). When the machine is moving, supply oil from the propel pump enters the motor. Supply oil is directed to the inlet port of valve plate (11). Supply oil is also directed to flushing spool (10). The valve plate directs oil into the piston chamber in cylinder block (7). This pressure forces the pistons which are aligned with the inlet port to move out of the cylinder block.As pistons (8) are forced out of cylinder block (7), slipper feet (9) slide along the swashplate. This action causes the cylinder block and pistons to rotate. Since the cylinder block is splined to output shaft (13), the output shaft also rotates. As cylinder block (7) rotates, pistons (8) align with the outlet port in valve plate (11). The rotation of the cylinder block