Service Manual

310-0510 IHT 3
HYDRAULIC SCHEMATIC
Figure 2 provides an illustration of the hydraulic
oil circuit. The oil supply for the hydraulic
system of the 310-0510 IHT is also utilized for
lubricating the components of the final drive
assembly.
The input shaft and pump cylinder block are
turned in one direction only by the engine/drive
belt/pulley combination. Output of the oil flow is
controlled by the direction and amount that the
variable swashplate is angled. As the pump
pistons compress they force the oil to flow
through one of two passageways (forward or
reverse) in the center section to the motor
cylinder block and motor shaft. Since the motor
has a fixed displacement angle it is forced to
turn with the flow of oil. As the angle of the
pump swashplate is increased the amount of oil
being pumped will increase and cause a higher
speed output of the motor. Reversing the angle
of the swashplate will reverse the direction of
oil flow.
During the operation of the transaxle, fluid is
“lost” from the hydraulic loop through leak paths
designed into the product for lubrication
purposes (around pistons, under the rotating
cylinder blocks, etc.). This “lost” fluid returns to
the transaxle housing, then is pulled back into
one of the check valves depending upon the
direction of vehicle operation. All of this oil
must pass through an internal filter.
The motor cylinder block mounts onto a splined
motor shaft which drives the gear train.
The bypass feature in the 310-0510 has a
mechanical lever which lifts the check valve
balls off their seat. This allows oil flow from the
cylinder blocks to be discharged.
Figure 2. 310-0510 Hydraulic Flow Illustration
INPUT SHAFT
RESERVOIR
TRANSAXLE HOUSING
CHECK VALVE
BYPASS ACTUATOR
VARIABLE SWASH PLATE
DISPLACEMENT PUMP
10 CC VARIABLE
FILTER ASSEMBLY
CHECK VALVE
DIFFERENTIAL ASSEMBLY
FIXED DISPLACEMENT ANGLE
CYLINDER BLOCK ASSEMBLY
CYLINDER BLOCK ASSEMBLY
10 CC FIXED
DISPLACEMENT MOTOR