Service Manual

XL Lawn Tractor Service Manual 3 - 3
XL HYDROSTATIC TRANSAXLES
Purging Procedures
Due the effects air has on efficiency in hydrostatic drive
applications, it is critical that it be purged from the
system.
These purge procedures should be implemented any
time a hydrostatic system has been opened to facilitate
maintenance or any additional oil has been added to
the system.
Air creates inefficiency because its compression and
expansion rate is higher than that of the oil normally
approved for use in hydrostatic drive systems.
The resulting symptoms in hydrostatic systems may
be:
1. Noisy operation.
2. Lack of power or drive after short term operation.
3. High operation temperature and excessive
expansion of oil.
Before starting, make sure the transaxle is at the
specified oil level, page 3 - 1.
The following procedures should be performed with the
vehicle drive wheels off the ground, then repeated
under normal operating conditions.
1. With the bypass valve open and the engine
running, slowly move the directional control (foot
control) in both forward and reverse directions 5 to
6 times; as air is purged from the unit, the oil level
will drop.
2. With the bypass valve in the closed position and
the engine running, slowly move the directional
control valve (foot control) in both forward and
reverse directions 5 to 6 times. After stopping the
engine, check the oil level and add oil as required.
3. It may be necessary to repeat Steps 1 and 2 until
all the air is completely purged from the system.
When the transaxle moves forward and reverse at
normal speed purging is complete.
Fluid Change
The Hydro-Gear transaxle is factory filled, sealed and
does not require oil maintenance. However, in the
event of oil contamination or degradation, oil
replacement may correct certain performance
problems.
Remove the transaxle from the vehicle and drain the oil
from the top fluid fill port. Fill unit as near the top of fill
port as is practical. Tipping the unit forward, backward
and from side to side will allow air to escape. The
tipping and filling activity may need to be repeated
several times. Refer to the oil fill range for the Hydro-
Gear model transaxle. Reinstall transaxle and perform
purging procedures.
If the oil drained from the transaxle is severely
contaminated or overheated, the transaxle should be
disassembled for inspection, cleaning, and repair, as
needed.
HXL Hydro Transaxle Removal -
2000 and Prior
1. Disconnect battery cables and remove the battery
and battery tray. Remove the mower deck (refer
to "Mower" section on page 6 - 1).
2. Raise the rear of the tractor and remove the right
and left rear tires. Put jack stands under the
frame, just in front of the transaxle (Figure 72).
Figure 72
MVC-0038