Cub Cadet ZD - Manual (Page 6)

EZT ® 3
HYdraulic scHEMaTic
Figure 2 provides an illustration of the hydraulic
oil circuit. The oil supply for the hydraulic sys-
tem of the EZT ® 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 mo-
tor 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 pump 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 EZT has a mechanical
lever which lifts the motor block off of the center
section running surface. This allows oil flow
from the cylinder blocks to be discharged.
figure 2. Hydraulic flow illustration
EZT ® HYdraulic flow scHEMaTic