Hydro-Gear 310-1500 Installation and operating manual

310-1500/310-1700
Integrated Hydrostatic Transaxle
Service and Repair Manual
BLN-52178
December 2008
Digitally signed by WMV-Dresden
DN: cn=WMV-Dresden, c=DE,
o=WMV-Dresden,
[email protected]
Date: 2017.01.26 09:49:46 +01'00'
WMV-
Dresden

TABLE OF CONTENTS
Section Page
Foreword .............................................................................................................................. 1
Description and Operation ................................................................................................. 2
Introduction.......................................................................................................................... 2
General Description ..................................................................................................................................... 2
Introduction .................................................................................................................................................. 2
Hydraulic Schematic ................................................................................................................................. 3-5
Product Identification ................................................................................................................................... 6
Technical Specifications............................................................................................................................... 7
Safety.................................................................................................................................... 8
Personal Safety............................................................................................................................................ 8
Tool Safety ................................................................................................................................................... 8
Work Area Safety ......................................................................................................................................... 8
Servicing Safety ........................................................................................................................................... 8
Troubleshooting .................................................................................................................. 9
Service and Maintenance.................................................................................................. 10
External Maintenance ................................................................................................................................ 10
Service and Maintenance Procedures ....................................................................................................... 10
Fluids ..........................................................................................................................................................11
Brake Maintnenance .................................................................................................................................. 12
Return to Neutral Setting Foot Control....................................................................................................... 13
Purging Procedures ................................................................................................................................... 14
Repair ................................................................................................................................. 15
General Instructions................................................................................................................................... 15
Required Tools ........................................................................................................................................... 15
Torque Specifications................................................................................................................................. 15
Transaxle Removal .................................................................................................................................... 15
Limited Disassembly .................................................................................................................................. 15
How To Use This Manual ........................................................................................................................... 16
Brake Assembly .................................................................................................................................... 17,18
Bypass Assembly....................................................................................................................................... 19
Control Assembly .................................................................................................................................. 20,21
Seal Kit Replacement ................................................................................................................................ 22
Torque Bracket Assembly .......................................................................................................................... 23
Fan and Pulley Assembly........................................................................................................................... 24
Input Shaft Assembly ................................................................................................................................. 25
Auxiliary Pump ........................................................................................................................................... 26
Charge Pump Assembly ............................................................................................................................ 27
Lower Housing/FIlter/Manifold Assembly.............................................................................................. 27,29
Planetary Differential Assembly ............................................................................................................ 30-33
Motor/Center Section/Pump Assembly ................................................................................................. 34-36
Directional Control Assembly ..................................................................................................................... 37
Transaxle Installation ................................................................................................................................. 38
Assembly After a Complete Teardown ....................................................................................................... 38
Sealant Application .................................................................................................................................... 39
Parts List ....................................................................................................................... 40-43
Glossary of Terms ........................................................................................................ 44,45

-1500/-1700 IHT 1
FOREWORD
Headquartered in Sullivan, Illinois, Hydro-Gear®
is a world leader in the design, manufacture,
and service of quality hydrostatic transaxles for
the lawn and garden industry. The mission of
our company is to be recognized by our custom-
ers and the industry as a world-class supplier
and the quality leader in everything we do.
This Service and Repair Manual is designed
to provide information useful in servicing and
troubleshooting the Hydro-Gear -1500 or -1700
Integrated Hydrostatic Transaxle (IHT).
Also included is a glossary of terms that are
frequently used throughout the industry and
in Hydro-Gear service publications. Under-
standing terminology is very important!
It is necessary, and a good shop practice, that
your service area be equipped with the proper
tools and the mechanics be supplied the latest
information available. All repair procedures il-
lustrated in this guide are suggested, but pre-
ferred methods of repair.
Repair procedures require that the transaxle
unit be removed from the vehicle.
This is not a certification, test or study guide for
a certification test. If a technician is interested
in certification, they should contact an agent
representing the OPEESA (Outdoor Power
Equipment and Engine Service Association)
at [phone] or their Hydro-Gear Central
Service Distributor. Many distributors will be
hosting certification testing. These study guides
will cover most of the products and manufac-
turers in our industry.
For more information about Hydro-Gear or our
products, please contact your Central Service
Distributor, or call our Customer Service De-
partment at [phone].

2-1500/-1700 IHT
INTRODUCTION
The purpose of this manual is to provide use-
ful information for servicing the Hydro-Gear®
-1500/ -1700 Integrated Hydrostatic Transaxles
(IHT). This manual includes transaxle gen-
eral description, hydraulic schematic, technical
specifications, product identification, safety,
troubleshooting, maintenance, and repair pro-
cedures.
The transaxle normally will not require servic-
ing during the life of the vehicle in which it is
installed. Should other servicing be required,
the transaxle will need to be thoroughly cleaned
before beginning most procedures.
Please refer to the instructions titled “How to
Use This Manual” in the Repair Section for an
explanation of the layout of the disassembly,
inspection, and reassembly portions of this
manual.
GENERAL DESCRIPTION
The -1500/-1700 series transaxles are self con-
tained units designed for the transfer and con-
trol of power. They provide an infinitely variable
speed range between zero and maximum in
both forward and reverse modes of operation.
The transaxle uses a variable displacement
pump with a maximum displacement of 10
cc per revolution, and motor with a fixed dis-
placement of 21cc per revolution. The variable
displacement pump features a cradle swash-
plate with a direct-proportional displacement
control. Reversing the direction of the swash-
plate reverses the flow of oil from the pump
and thus reverses the direction of the motor
output rotation. The pump and motor are of the
axial piston design and utilize spherical nosed
pistons which are held against a thrust race by
internal compression springs.
The -1500/-1700 series transaxles have a self
contained fluid supply and an internal filter. The
fluid is drawn through the internal reservoir and
feeds the fixed displacement gerotor charge
pump. Excess fluid in the charge circuit is dis-
charged over the charge relief valve and dumps
back to case. Charge check valves in the center
section are used to control the makeup flow of
the fluid to the low pressure side of the loop.
The transaxle is filled and tested at the factory
and should not require fluid or filter changes
unless the fluid becomes contaminated.
A cam style, block lifting bypass is utilized in the
-1500/-1700 series to permit moving the vehicle
for a short distance at a maximum speed of 2
m.p.h. (3.2 km/hr) without starting the engine.
WARNING
Actuating the bypass will result in the
loss of hydrostatic braking capacity. The
machine must be stationary on a level
surface and in neutral when actuating
the bypass.
The -1500/-1700 series transaxles utilize an
in-line floating disc brake controlled by a "cam"
style actuating arm.
SECTION 1. DESCRIPTION AND OPERATION

-1500/-1700 IHT 3
Figure 1. -1500 Hydraulic Schematic
HYDRAULIC SCHEMATIC
Figure 2. -1700 Hydraulic Schematic
Figure 3. -1700 Hydraulic Schematic with Auxiliary Pump

4-1500/-1700 IHT
HYDRAULIC SCHEMATIC
Figures 4 and 5 provide illustrations of the hy-
draulic oil circuit. The oil supply for the hydraulic
system of the IHT is also utilized for the lubri-
cation of the planetary differential drive gears.
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 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 (or valve body) 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
swashplate is increased the amount of oil being
pumped will increase and cause a higher RPM
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
Figure 4. -1500 Hydraulic Flow Illustration
to the transmission housing and must be made
up in the loop. A charge pump is included on
the IHT to supply this makeup flow. The make
up flow is controlled (or directed) by the check
valves. Each check valve will either be held
opened or closed (depending upon the direction
of vehicle operation) by the system operating
pressure (closed) or by charge pressure (open)
from the charge pump.
The charge pump maintains a continuous flow
of oil as long as the input shaft is turning. All of
the oil being pulled into the charge pump first
must pass through an internal filter. Any oil not
needed by the transmission for make up flow
is discharged through the charge relief valve.
The charge relief valve maintains the charge
pressure.
The motor cylinder block mounts onto the
splined motor shaft which drives the planetary
differential gear/differential assembly.
The bypass feature in the IHT has a mechanical
lever which lifts the motor block off of the center
section running surface, allowing any oil flowing
from the pump block to be discharged into the
housing without turning the motor.

-1500/-1700 IHT 5
HYDRAULIC SCHEMATIC
Figure 5. -1700 Hydraulic Flow Illustration

6-1500/-1700 IHT
EXTERNAL FEATURES
-1500 AND -1700

-1500/-1700 IHT 7
TECHNICAL
SPECIFICATIONS
Technical specifications for the -1500 and -1700
IHT’s are given in Table 1.
Table 1. Technical Specifications
PRODUCT IDENTIFICATION
The model and configuration of the -1500 or
-1700 IHT can be determined from the label
shown in Figure 6.
Figure 6. -1700 Configuration Label
H Y D R O - G E A R
SULLIVAN, IL. U.S.A.
I IIIIIII IIII II II
165758 310-3000
I II IIII IIII IIIIII I II IIII
8 328 T1 476 Made in U.S.A.
Year Built
Date
(Julian - day of year)
Type of Product and Build Information
Serial Number
(unique number for that model - for that day)
OEM Model
Number
Hydro-Gear
Number
312-1700
Model
Number
Model
Reference
Number
-1500 -1700
Overall Transaxle
Reduction 24.6:1 24.6:1
Input Speed (rpm) 3000 max.
1800 min.
3600 max.
1800 min.
Maximum Tire Diameter 20 in. (508 mm) 23 in. (584 mm)
Axle Shaft Diameter 1.00 in. (25.4 mm) 1.00 in. (25.4 mm)
Axle Shaft End Options
4-Bolt Flange
Splined
4-Bolt Flange
Splined
Brake Type Disc Disc
Weight of Unit 53 lb. (24 kg) 53 lb. (24 kg)

8-1500/-1700 IHT
SECTION 2. SAFETY
PERSONAL SAFETY
Certain safety precautions must be observed
while servicing or repairing the IHT. This sec-
tion addresses some of these precautions but
must not be considered an all-inclusive source
on safety information. This section is to be
used in conjunction with all other safety material
which may apply, such as:
1) Other manuals pertaining to this ma-
chine
2) Local and shop safety rules and codes
3) Governmental safety laws and regu-
lations
Be sure that you know and understand the
equipment and the hazards associated with it.
Do not place speed above safety.
Notify your supervisor whenever you feel there
is any hazard involving the equipment or the
performance of your job.
Never allow untrained or unauthorized per-
sonnel to service or repair the equipment.
WARNING
POTENTIAL FOR SERIOUS INJURY
Inattention to proper safety, operation, or
maintenance procedures could result in
personal injury, or damage to the equip-
ment. Before servicing or repairing the
IHT, fully read and understand the safety
precautions described in this section.
Wear appropriate clothing. Loose or hanging
clothing or jewelry can be hazardous. Use the
appropriate safety equipment, such as eye
and hearing protection, and safety-toe and
slip-proof shoes.
Never use compressed air to clean debris from
yourself or your clothing.
TOOL SAFETY
Use the proper tools and equipment for the
task.
Inspect each tool before use and replace any
tool that may be damaged or defective.
WORK AREA SAFETY
Keep the work area neat and orderly. Be sure
it is well lit, that extra tools are put away, trash
and refuse are in the proper containers, and dirt
or debris have been removed from the working
areas of the machine.
The floor should be clean and dry, and all ex-
tension cords or similar trip hazards should be
removed.
SERVICING SAFETY
Certain procedures may require the vehicle to
be disabled in order to prevent possible injury
to the servicing technician and/or bystanders.
The loss of hydrostatic drive line power may
result in the loss of hydrostatic braking capabil-
ity. Proper brake maintenance is very important
should this condition develop.
Some cleaning solvents are flammable. Use
only approved cleaning materials: do not use
explosive or flammable liquids to clean the
equipment.
To avoid possible fire do not use cleaning sol-
vents in an area where a source of ignition may
be present
Discard used cleaning material in the appropri-
ate containers.
This symbol points out important
safety instructions which, if not followed, could
endanger the personal safety and/or property
of yourself and others. Read and follow all
instructions in this manual before attempting
maintenance on your transaxle. When you see
this symbol - HEED ITS WARNING.