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We set the wheels in motion.
310-2400
Integrated Zero-Turn Transaxle
Service and Repair Manual
BLN-51134
March 2001
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Table of Contents
Section Page
Foreword ........................................................................................................................................ 1
Section 1 Description and Operation .......................................................................................... 2
Introduction ........................................................................................................................................................ 2
General Description ............................................................................................................................................ 2
Hydraulic Schematic ........................................................................................................................................... 3
External Features 310-2400L ............................................................................................................................. 4
External Features 310-2400R ............................................................................................................................. 5
Technical Specifications ..................................................................................................................................... 6
Product Identification .......................................................................................................................................... 6
Section 2 Safety .............................................................................................................................7
Personal Safety .................................................................................................................................................. 7
Tool Safety ......................................................................................................................................................... 7
Work Area Safety ............................................................................................................................................... 7
Servicing Safety ................................................................................................................................................. 7
Section 3 Troubleshooting ........................................................................................................... 8
Section 4 Service and Maintenance ............................................................................................. 9
External Maintenance ......................................................................................................................................... 9
Service and Maintenance Procedures ................................................................................................................ 9
Fluids ............................................................................................................................................................... 10
Purging Procedures .......................................................................................................................................... 11
Return to Neutral Setting .................................................................................................................................. 12
Brake Maintenance .......................................................................................................................................... 13
Friction Pack Adjustment .................................................................................................................................. 13
Section 5 Repair .......................................................................................................................... 14
How To Use This Section ................................................................................................................................. 14
General Instructions ......................................................................................................................................... 14
Transaxle Removal .......................................................................................................................................... 14
Limited Disassembly ........................................................................................................................................ 14
Tools and Torques ........................................................................................................................................... 15
Back Cover ...................................................................................................................................................... 16
Brakes ........................................................................................................................................................17-18
Brake Shaft & Bevel Gear ................................................................................................................................ 19
Axle Shaft & Spur Gear ............................................................................................................................... 20-21
Lower Housing and Filter .................................................................................................................................. 22
Motor Shaft & Bevel Gear ................................................................................................................................. 23
Center Section, Cylinder Blocks and Bypass ...............................................................................................24-25
Input Shaft & Trunnion Arm ......................................................................................................................... 26-27
Transaxle Installation ....................................................................................................................................... 28
Assembly After a Complete Teardown .............................................................................................................. 28
Sealant Application ..................................................................................................................... 29
Parts List ................................................................................................................................. 30-31
Glossary of Terms ..................................................................................................................32-33
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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
customers 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 the
Hydro-Gear 310-2400, referred to as the
Integrated Zero Turn (IZT).
Also included is a glossary of terms that are
frequently used throughout the industry and in
Hydro-Gear service publications. Understanding terminology is very important!
It is necessary, and good shop practice, that
your service area be equipped with proper tools
and the mechanics to be supplied with the
latest information available. All repair
procedures illustrated in this guide are
suggested, but preferred methods of repair.
Some repair procedures require that the IZT 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 ESA (Engine Service Association) (610) 363-3844 or their Hydro-Gear Distributor. Many distributors will be hosting
certification testing. These study guides will
cover most of the products and manufacturers
in our industry.
For more information about Hydro-Gear or our
products, please contact your Central Service
Distributor, or call our Customer Service
Department at (217) 728-2581.
310-2400 IZT
1
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SECTION 1. DESCRIPTION AND OPERATION
INTRODUCTION
The purpose of this manual is to provide
information useful in servicing the Hydro-Gear
Integrated Zero Turn (IZT) transaxle. This manual includes the IZT’s general description, hydraulic schematic, technical specifications, servicing and troubleshooting procedures.
The transaxle normally will not require servicing
during the life of the vehicle in which it is
installed. Should other servicing be required,
the exterior of the transaxle will need to be
thoroughly cleaned before beginning most
procedures.
GENERAL DESCRIPTION
The 310-2400 is a self contained unit designed
for the transfer and control of power. It provides
an infinitely variable speed range between zero
and maximum in both forward and reverse
modes of operation.
This transaxle uses a variable displacement
pump with a maximum displacement of 10cc
per revolution, and motor with a fixed displacement of 21cc per revolution. The variable displacement pump features a cradle mounted
swashplate with a direct-proportional displacement control. Reversing the direction of the
swashplate 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 310-2400 has a self contained fluid supply
and an internal filter. The fluid is forced through
the filter by a positive “head” on the fluid in the
housing/expansion tank with an assist by the
negative pressure created in the pump pistons
as they operate.
The check valves in the center section are used
to control the makeup flow of the fluid to the low
pressure side of the loop.
A bypass is utilized in the 310-2400 to permit
moving the vehicle for a short distance at a
maximum of 2 m.p.h. (3.2 Km/h) 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 310-2400 is configured for both floating
disc and cog style parking brakes.
Figure 1. 310-2400 Hydraulic Schematic
2
310-2400 IZT
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CYLINDER BLOCK
ASSEMBLY
FIXED
SWASHPLATE
FIXED
DISPLACEMENT
21cc MOTOR
MOTOR
SHAFT
INPUT
SHAFT
VARIABLE
SWASHPLATE
CYLINDER
BLOCK
ASSEMBLY
VARIABLE
DISPLACEMENT
10cc PUMP
CHECK VALVE
CHECK VALVE
BYPASS
ACTUATOR
TRANSAXLE
HOUSING
RESERVOIR
FILTER
Figure 2. 310-2400 Hydraulic Flow Illustration
HYDRAULIC SCHEMATIC
Figure 2 provides an illustration of the hydraulic
oil circuit. The oil supply for the hydraulic
system of the 310-2400 IZT 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.
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 310-2400 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.
During the operation of the transaxle, fluid is
“lost” from the hydraulic loop through leak paths
310-2400 IZT
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EXTERNAL FEATURES 310-2400L
Back Cover
Back Cover
Axle Shaft
Disc Brake Assembly
Fill Port
Input Shaft
Hub
Assembly
Bypass
Actuator
Cog Brake Assembly
4
Seal Plug
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Lower Cover
Control Arm
Assembly
310-2400 IZT
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EXTERNAL FEATURES 310-2400R
Back Cover
Back Cover
Axle Shaft
Hub
Assembly
Bypass
Actuator
Input Shaft
Disc Brake Assembly
Fill Port
310-2400 IZT
Control Arm
Assembly
Lower Cover
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Seal Plug
Cog Brake Assembly
5
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TECHNICAL SPECIFICATIONS
Technical specifications for the 310-2400 IZT are listed in Table 1.
Overall Transaxle Reduction
19.2:1
Input Speeds
Maximum: 3000 RPM
Minimum: 1800 RPM
Tire Diameter
18 in; 45.7cm with 325 lbs; 147.4 kg
maximum weight on tires
Table 1. 310-2400 Technical Specifications
Axle Shaft Options
Type: Keyed / Double “D”
Diameter: 0.984 inch; 25.0 mm
Type: Flanged
Diameter: Hub
Brake Type
Disc, Parking
Cog, Parking
Weight of Unit
30 lb; 14 kg
PRODUCT IDENTIFICATION
The model and configuration of the 310-2400 IZT can be determined from the label shown in
Figure 3.
H Y D R O - G E A R
H Y D R O - G E A R
SULLIVAN, IL. U.S.A.
SULLIVAN, IL. U.S.A.
I IIII III IIII II II
I IIII III IIII II II
Model
Model
Number
Number
Year Built
Year Built
Date
Date
(Julian - day of year)
(Julian - day of year)
13054 318-2400
13054 318-2400
I II IIII IIII II I III I II IIII
I II IIII IIII II I III I II IIII
0 319 Z1401 Made in U.S.A.
0 319 Z1401 Made in U.S.A.
Type of Product and Build Information
Type of Product and Build Information
318-2400L
Serial Number
Serial Number
(unique number for that model - for that day)
(unique number for that model - for that day)
Figure 3. 310-2400 Configuration Label
Hydro-Gear
Hydro-Gear
Ref. Number
Ref. Number
6
310-2400 IZT
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SECTION 2. SAFETY
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.
WARNING
POTENTIAL FOR SERIOUS INJURY
Inattention to proper safety, operation, or
maintenance procedures could result in personal injury, or damage to the equipment.
Before servicing or repairing the 310-2400
IZT, 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 slipproof 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.
PERSONAL SAFETY
Certain safety precautions must be observed
while servicing or repairing the 310-2400 IZT.
This section addresses some of these
precautions but must not be considered an allinclusive 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 machine,
2) Local and shop safety rules and codes,
3) Governmental safety laws and regulations.
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 personnel to service or repair the equipment.
The floor should be clean and dry, and all extension 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 capability.
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 solvents in an area where a source of ignition may
be present.
Discard used cleaning material in the appropriate containers.
310-2400 IZT
7
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SECTION 3. TROUBLESHOOTING
WARNING
Do not attempt any servicing or adjustments with the engine running.
Use extreme caution while inspecting the
drive belt assembly, and all vehicle linkage!
Follow all safety procedures outlined in
the vehicle owner’s manual!
Table 2. 310-2400 Troubleshooting Checklist
UNIT OPERATES IN ONE DIRECTION ONLY
Control linkage bent or out of adjustment
Drive belt slipping or pulley damaged
VEHICLE DOES NOT DRIVE/TRACK STRAIGHT
Vehicle tires improperly inflated
Control linkage bent, loose or out of adjustment
Bypass partially engaged
In many cases problems with the 310-2400 IZT
are not related to a defective transaxle, but are
caused by slipping drive belts, partially
engaged bypass valves, and loose or
damaged control linkages. Be sure to perform
all operational checks and adjustments outlined
in Section 4, Service and Maintenance before
assuming the unit is malfunctioning. Table 2
below provides a troubleshooting check list to
help determine the cause of operational problems.
Corrective Action Possible Cause
Repair or replace linkage, Page 9
Repair or replace drive belt or pulley, Page 9
Refer to vehicle manufacturer suggested pressure
Repair, adjust or replace vehicle linkage
Adjust bypass linkage
Oil level low or contaminated oil
Excessive loading
Brake setting incorrect
Loose parts
Bypass assembly sticking
Air trapped in hydraulic system
Engine speed low
Control linkage bent or out of adjustment
Brake setting incorrect
Drive belt slipping or pulley damaged
Oil level low or contaminated oil
Excessive loading
Bypass assembly sticking
Air trapped in hydraulic system
Debris buildup around transaxle
Brake setting incorrect
Cooling fan damaged
Oil level low or contaminated oil
Excessive loading
Air trapped in hydraulic system
UNIT IS NOISY
Fill to proper level or change oil, Page 10
Reduce vehicle loading, Page 9
Adjust brake to proper setting, Page 13
Repair or replace loose parts
Repair or replace valve or linkage
Purge hydraulic system, Page 11
UNIT HAS NO/LOW POWER
Adjust to correct setting
Repair or replace linkage, Page 9
Adjust brake to proper setting, Page 13
Repair or replace drive belt or pulley, Page 9
Fill to proper level or change oil, Page 10
Reduce vehicle loading, Page 9
Repair or replace valve or linkage
Purge hydraulic system, Page 11
UNIT OPERATING HOT
Clean off debris, Page 9
Adjust brake to proper setting, Page 13
Repair or replace cooling fan
Fill to proper level or change oil, Page 10
Reduce vehicle loading, Page 9
Purge hydraulic system, Page 11
Damaged seals, housing, or gaskets
Air trapped in hydraulic system
8
TRANSAXLE LEAKS OIL
Replace damaged component
Purge hydraulic system, Page 11
310-2400 IZT
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SECTION 4. SERVICE AND MAINTENANCE
NOTE: Any servicing dealer attempting
a warranty repair must have prior
approval before conducting maintenance
of a Hydro-Gear product unless the
servicing dealer is a current Authorized
Hydro-Gear Service Center.
EXTERNAL MAINTENANCE
Regular external maintenance of the 310-2400
IZT should include the following:
1. Check the vehicle operator’s manual for
the recommended load ratings. Insure
the current application does not exceed
load rating.
2. Check oil level in accordance with Figure 4
Page 10.
3. Inspect the vehicle drive belt, idler pulley(s),
and idler spring(s). Insure that no belt
slippage can occur. Slippage can cause low
input speed to the transmission.
SERVICE AND MAINTENANCE
PROCEDURES
All the service and maintenance procedures
presented on the following pages can be
performed while the 310-2400 is mounted on
the vehicle. Any repair procedures as
mentioned in the repair section of this manual
must be performed after the unit has been
removed from the vehicle.
4. Inspect the transmission cooling fan for
broken or distorted blades and remove any
obstructions (grass clippings, leaves, dirt,
etc.).
5. Inspect the axle parking brake and vehicle
linkage to insure proper actuation and
adjustment of the parking brake.
6. Inspect the vehicle control linkage to the
directional control arm on transaxle. Also,
insure the control arm is securely fastened
to the trunnion arm of the transaxle.
7. Inspect the bypass mechanism on the
transaxle and vehicle linkage to insure it
actuates and releases fully.
310-2400 IZT
9
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