8 HGM-H
all parts must be kept free of foreign material
and chemicals.
Protect all exposed sealing surfaces and open
cavities from damage and foreign material. The
external surfaces should be cleaned before
beginning any repairs. Do not use a pressure
washer to clean the transaxle.
FLUIDS
The uids used in Hydro-Gear products have
been carefully selected, and only equiva-
lent, or better products should be substituted
Typically, an engine oil with a minimum rating
of 9.0 cSt (55 SUS) at 230°F (110° C) and anAPI
classication of SL is recommended. Refer to the
vehicle manufacturer for recommended oil.
“All uids should be handled and disposed of
according to local, state, and federal regula-
tions.”
FLUID VOLUME AND LEVEL
Certain situations may require additional uid to
beadded or even replaced.In addition to lling
the hydraulic system with uid, an additional
34 . oz. (1000mL) will need to be added to the
case via the highest ll point of the HGM-H
unit. Reference page 4 for the proper ll loca-
tion. Refer to the vehicle manufacturer’s recom-
mendations for the proper ll location and level of
thecompletehydraulicsystem.Aftermaintenance
oroil change, followpurging procedures onpage
9 and check the uid level once the unit has been
purged and operated for 1 minute.
FLUID CHANGE
In the event of oil contamination or
degradation, oil addition or change may
alleviate certain performance problems. Refer
to the vehicle manufacturer’s recommended oil
change frequency. Refer to purging procedures
on page 9 after changing uids.
FILTERS
An inlet lter is required to insure that only clean
uid enter the system. Refer to the vehicle manu-
facturer for approved lter replacement.
SERVICE AND MAINTENANCE
EXTERNAL MAINTENANCE
Regular external maintenance of the hydraulic
motor should include the following:
1. Checkthevehicle operator’smanual for the
recommended load ratings. Insure that the
current application does not exceed load
rating.
2. Checkreservoiroillevelinaccordance with
the vehicle manufacturers recommenda-
tions.
3. Inspectthevehicle drive belt, idlerpulley(s),
and idler spring(s). Insure that no belt slip-
page can occur. Slippage can cause low
input speed to the pump resulting in low
ow to the hydraulic motor.
4. Inspect the vehicle control linkage to the
directionalcontrol armon thevehiclespump
assembly.
5. Inspect the hydraulic motors and pumps
for debris. Keeping the units debris free is
important in the overall performance of the
unit.
6. Inspect all external plumbing for possible
leaks or loose ttings. An air leak may be
difcult to detect on the “suction side” or inlet
line to the pump. Refer to Purging Proce-
dure on page 9.
SERVICE AND MAINTENANCE
PROCEDURES
Some of the service procedures presented on
thefollowing pages can be performed while the
transaxleismounted on the vehicle.Anyrepair
procedures as mentioned in the repair section
of this manual must be performed after the unit
has been removed from the vehicle.
Cleanliness is a primary means of assuring
satisfactory life on repaired units. Thoroughly
clean all exposed surfaces prior to any type
of maintenance. Cleaning of all parts by us-
ing a solvent wash and air drying is usually
adequate. As with any precision equipment,
