Toro 23515, 33515, 23510, 33510 Service Manual
T2® / T2-HP™ / T3 HD™
Integrated Hydrostatic Transaxle
Service and Repair Manual
BLN-52749
February 2013
TABLE OF CONTENTS
Foreword ............................... . . . .1
Description and Operation ................. . . . .2
Introduction ............................. . . . .2
Hydraulic Schematic ...................... . . . .3
External Features ........................ . . 4-5
Technical Specifications ................... . . . .6
Product Identification ...................... . . . .6
Safety ................................. . . . .7
Personal Safety .......................... . . . .7
Tool Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Work Area Safety ........................ . . . .7
Servicing Safety
Troubleshooting .......................... . . . .8
Service and Maintenance .................. . . . .9
External Maintenance ..................... . . . .9
Service and Maintenance Procedures ........ . . . .9
Fluids .................................. . . . .9
......................... . . . .7
RH Axle Shaft
Bull Gear Set ............................ . . .25
Reduction Gear Set ....................... . . .26
Input Shaft .............................. . . .27
Swashplate ............................. . . .28
Bypass Arm ............................. . . .29
Center Section, Motor Shaft & Motor Block .... . . .30
Filter Assembly .......................... . . .31
Cylinder Blocks .......................... . . .31
LH Axle Shaft ........................... . . .32
Expansion Tank Hose and Fitting ........... . . .33
Assembly after Teardown .................. . . .34
Side Housing-Screw Sequence ............. . . .35
T2® / T2-HPTM Transaxle Exploded View ...... . . .36
T3 HDTM Transaxle Exploded View .......... . . .38
Glossary of Terms ........................ . . .40
........................... . . .24
Fluid Volume and Level .................... . . . .9
Fluid Change Procedure ................... . . .10
Purging Procedures ....................... . . .11
Return To Neutral Setting .................. . . .12
Brake Maintenance ....................... . . .13
Friction Pack Adjustment ................... . . .13
Tear Down and Reassembly ................ . . .14
How to Use This Manual ................... . . .14
General Instructions
Tools .................................. . . .15
Torques ................................ . . .15
Transaxle Removal ....................... . . .16
Fan and Pulley ........................... . . .17
Expansion Tank .......................... . . .18
Control Arm Assembly ...................... . 19
Return to Neutral Option ................... . . .20
Return to Neutral/ROS Assembly Option .........21
...................... . . .14
Brake Arm & Brake Assembly ............... . . .22
Side Housing ............................ . . .23
T2® / T2-HPTM / T3 HDTM i
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 and
troubleshooting the Hydro-Gear T2®, T2-HPTM
and T3 HDTM Integrated Hydrostatic Transaxles.
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 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
illustrated in this guide are suggested, but preferred methods of repair.
Internal repair procedures require that the
transaxle unit be removed from the vehicle.
This is not a certication, test or study guide for
a certication test. If a technician is interested
in certication, they should contact an agent
representing the EETC (Equipment and Engine
Training Council) at (262) 367-6700 or their
Hydro-Gear Central Service Distributor. Many
distributors will be hosting certication 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 visit our Customer Service Department website at www.hydro-gear.com.
T2® / T2-HPTM / T3 HDTM 1
DESCRIPTION AND OPERATION
INTRODUCTION
The purpose of this manual is to provide information useful in servicing the Hydro-Gear
®
T2®,
T2-HPTM and T3 HDTM Integrated Hydrostatic
Transaxle. This manual includes the T2, T2HP and T3 HD’s general description, hydraulic
schematic, technical specications, 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. Do not wash the transaxle while it
is hot. Do not use a pressure washer to clean
the unit.
GENERAL DESCRIPTION
The T2, T2-HP and T3 HD are self contained
units designed for the transfer and control of
power. They provide an innitely variable speed
range between zero and maximum in both forward and reverse modes of operation.
nosed pistons which are held against a thrust
race by internal compression springs.
The T2, T2-HP and T3 HD have a self contained
uid supply and an internal lter. The uid is
forced through the lter by a positive “head” on
the uid 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 ow of the uid to the low
pressure side of the loop.
A block lifting bypass is utilized in the T2, T2HP and T3 HD 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. The T2,
T2-HP and T3 HD utilize an in-line oating disc
brake controlled by a “cam” style actuating arm.
These transaxles uses a variable displacement pump with a maximum displacement
of 8cc per revolution, and motor with a xed
displacement of 10.2cc for the T2 / T2-HP and
12cc for the T3 HD per revolution. The variable displacement pump features a trunnion
mounted swashplate with a direct-proportional
displacement control. Reversing the direction
of the swashplate reverses the ow 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
2 T2® / T2-HPTM / T3 HD
TM
DESCRIPTION AND OPERATION (CONTINUED)
HYDRAULIC SCHEMATIC
Figure 1 is a schematic of the hydraulic oil circuit. The oil supply for the hydraulic system of
the T2®, T2-HPTM and T3 HDTM is also utilized
for lubricating the components of the nal 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 ow is
controlled by the direction and amount that the
variable swashplate is angled. As the pump pis-
tons compress they force the oil to ow 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 xed
displacement angle it is forced to turn with the
ow 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 ow.
During the operation of the transaxle, uid
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” uid returns
to the transaxle housing, then is pulled back
into one of the check valves depending on the
direction of vehicle operation. All of this oil
must pass through an internal lter.
The motor cylinder block mounts onto a splined
motor shaft which drives the gear train.
The bypass feature in the T2, T2-HP and T3
HD has a mechanical lever which lifts the motor block off the center section running surface.
This allows oil ow from the cylinder blocks to
be discharged.
T2® / T2-HPTM / T3 HDTM 3
Figure 1, T2 Hydraulic Schematic
EXTERNAL FEATURES T2® / T2-HPTM / T3 HD
Bypass Arm
LH Axle RH Axle
TM
Control Arm
Input Shaft
Main HousingSide Housing
Oil Fill Plug
Expansion Tank
— Top View —
Input Shaft
Brake Arm
LH Axle RH Axle
Side Housing Main Housing
Control Arm
Expansion Tank
— Inboard View —
4 T2® / T2-HPTM / T3 HD
TM
EXTERNAL FEATURES T2® / T2-HPTM / T3 HD
Expansion Tank
RH Axle
TM
Bypass Arm
Control Arm
Bypass Arm
Brake Arm
— Outboard View—Left —
Pulley
Fan
Oil Fill Plug
Expansion Tank
LH Axle
Brake Rotor
— Outboard View—Right —
T2® / T2-HPTM / T3 HDTM 5
TECHNICAL SPECIFICATIONS
TECHNICAL SPECIFICATI ONS
Overall Transaxle Reduction
Input Speeds
Maximum Hi-Idle (No Load)
Minimum
Output Torque
Intermittent lb-ft (Nm)
Continuous lb-ft (Nm)
Weight on Tires (per unit)
Maximum with 16” tires lb (kg)
Maximum with 18” tires lb (kg)
Maximum with 20” tires lb (kg)
Axle Shaft Diameter in (mm)
Axle Shaft End Options
Parking Brake Type
Weight of Unit lb (kg)
®
T2
20.63:1 22 . 6 8.1 25.42:1 24.27:1 26.70:1 29.91:1.6
3000 rpm
1800 rpm
195 (264)
105 (142)
540 (245)
—
—
215 (291)
115 (156)
540 (245)
500 (227)
—
T2-HP
285 (197)
145 (196)
540 (245)
540 (245)
540 (245)
TM
230 (311)
140 (189)
630 (285)
—
—
.75 (19.05)
Keyed or Two Flats
External Disc
28 (12.7)
T3 HD
TM
3200 rpm
1800 rpm
290 (393)
150 (203)
—
630 (285)
—
300 (406)
160 (216)
—
—
630 (285)
PRODUCT IDENTIFICATION
The model and conguration of the T2, T2-HP and T3 HD can be determined from the label
shown below.
HYDRO-GEAR
Model Number
T2-AABC-2X1A-1CXX
6 352 K1 476
Year Built
Date (Julian- Day of year)
Serial Number (unique for that model - for that day)
Type of Product and Build Information
Assembled in USA
Figure 2, Conguration Label
6 T2® / T2-HPTM / T3 HD
TM
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.
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
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
T2®, T2-HPTM or T3 HDTM transaxle, fully
read and understand the safety precautions described in this section.
PERSONAL SAFETY
Certain safety precautions must be observed
while servicing or repairing the T2, T2-HP or
T3 HD. 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 regula-
tions.
Be sure that you know and understand the
equipment and the hazards associated with it.
Do not place speed above 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 oor 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.
Some cleaning solvents are ammable. Use
only approved cleaning materials. Do not use
explosive or ammable liquids to clean the
equipment.
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.
T2® / T2-HPTM / T3 HDTM 7
To avoid possible re, do not use cleaning
solvents in an area where a source of ignition
may be present.
Discard used cleaning material in the appropriate containers.
TROUBLESHOOTING
In many cases, problems with the T2®, T2-HPTM
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.
TROUBLESHOOTING CHECKLIST
Possible Cause Corrective Action
Unit Operates In One Direction Only
Control linkage bent or out of adjustment Repair or replace linkage, Page 9
Drive belt slipping or pulley damaged Repair or replace drive belt or pulley, Page 9
Vehicle Does Not Drive/Track Straight
Vehicle tires improperly inated Refer to vehicle manufacturer suggested pressure
Control linkage bent or out of adjustment Repair or replace linkage, Pages 9 and 12
Bypass assembly sticking Repair or replace bypass, Page 29
Brake Partially Engage Disengage Brake, Replace Broken or Missing Brake Return Spring
Unit Is Noisy
Oil level low or contaminated oil Fill to proper level or change oil, Page 10
Excessive loading Reduce vehicle loading, Page 9
Loose parts Repair or replace loose parts
Bypass assembly sticking Repair or replace linkage, Page 9
Air trapped in hydraulic system Purge hydraulic system, Page 11
Brake Partially Engage Disengage Brake, Replace Broken or Missing Brake Return Spring
Unit Has No/Low Power
Engine speed low Adjust to correct setting
Control linkage bent or out of adjustment Repair or replace linkage, Page 9
Drive belt slipping or pulley damaged Repair or replace drive belt or pulley, Page 9
Oil level low or contaminated oil Fill to proper level or change oil, Page 10
Excessive loading Reduce vehicle loading, Page 9
Bypass assembly sticking Repair or replace linkage, Page 9
Air trapped in hydraulic system Purge hydraulic system, Page 11
Brake Partially Engage Disengage Brake, Replace Broken or Missing Brake Return Spring
Unit Is Operating Hot
Debris buildup around transaxle Clean off debris, Page 9
Cooling fan damaged Repair or replace cooling fan, Pages 17
Oil level low or contaminated oil Fill to proper level or change oil, Page 10
Excessive loading Reduce vehicle loading, Page 9
Air trapped in hydraulic system Purge hydraulic system, Page 11
Brake Partially Engage Disengage Brake, Replace Broken or Missing Brake Return Spring
Transaxle Leaks Oil
Damaged seals, housing, or gaskets Replace damaged components
Air trapped in hydraulic system Purge hydraulic system, Page 11
8 T2® / T2-HPTM / T3 HD
and T3 HDTM 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 Service and Maintenance, before assuming
the transaxle is malfunctioning. The table below
provides a troubleshooting checklist to help
determine the cause of operational problems.
TM
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 T2®, T2-
TM
HP
and T3 HDTM 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 3
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 transaxle.
SERVICE AND MAINTENANCE
PROCEDURES
All the service and maintenance procedures
presented on the following pages can be
performed while the T2, T2-HP or T3 HD 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.
FLUIDS
The uids used in Hydro-Gear products have
been carefully selected, and only equivalent, 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 an API
classication of SL is recommended. A 20W-50
engine oil has been selected for use by the factory
and is recommended for normal operating
temperatures.
FLUID VOLUME AND LEVEL
4. Inspect the transaxle 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.
Fluid volume information is provided in the
Table below.
Certain situations may require additional uid
to be added or even replaced. Refer to Page
10, Figure 3 and pages 4 and 5 for the proper
ll port location.
Fill the T2, T2-HP or T3 HD to the bottom of the
oil ll port threads.
Recheck the uid level once the unit has been
operated for approximately 1 minute.
Purging may be required. Refer to the purging
procedures on page 11.
Fluid Description
Type: 20W50 motor oil
Fluid Volume (per transaxle)
10 Bolt Housing: 69.3 - 65.9 . oz. (2050 - 1950 ml)
14 Bolt Housing: 68.1 - 64.8 . oz. (2015 - 1915 ml)
T2® / T2-HPTM / T3 HDTM 9
FLUID CHANGE PROCEDURE
This transaxle is factory lled, sealed and does
not require oil maintenance. However, in the
event of oil contamination or degradation, oil
addition or change may alleviate certain performance problems.
1. Remove the transaxle from the vehicle.
2. Clean the expansion tank and oil ll port
areas of any debris.
3. Remove the oil ll port tting.
4. Position the transaxle so the oil will drain
completely out of the housing.
5. After all the oil is drained from the transaxle,
remove the expansion tank by removing the
self tapping bolt (10-32 x ½) and ratchet
fastener that holds the tank to the housing.
6. Remove the tank and drain the oil from the
tank. DO NOT remove the vent cap from the
tank. DO NOT remove the tank hose or
o-ring unless a replacement is needed.
7. Install the tank by rst inserting the hose
into the opening in the expansion tank.
Push the tank opening over the o-ring to
ensure a proper seal.
8. Install the tank and self tapping bolt making
sure not to cross thread the bolt. Torque the
bolt to the lower value of the torque speci-
cation listed in the Table on page 15.
9. Fill the transaxle at the oil ll port according
to Figure 3.
10. Install the oil ll port tting.
EXPANSION TANK FUNCTION
The expansion tank allows the T2
and T3 HDTM to operate free of air entrainment and provides maximum lubrication to the
mechanical and hydraulic components in the
transaxle.
As the T2, T2-HP or T3 HD transaxle is operated, oil in the transaxle housing heats up which
causes the oil to expand. The oil ows through
an internal hose to the bottom of the vented
expansion tank. As the oil cools, the oil in the
transaxle housing contracts, causing the oil
level to go down in the housing. This creates a
negative pressure in the housing causing the
oil to be drawn back into the case. This keeps
the transaxle housing full of oil at specied
operating temperatures.
®
, T2-HPTM
Top of Fill Port
1.25”
.50”
Oil Level
Expansion Tank
Fluid Description
Type: 20W50 motor oil
Figure 3, Expansion Tank
Fluid Volume (per transaxle)
10 Bolt Housing: 69.3 - 65.9 . oz. (2050 - 1950 ml)
14 Bolt Housing: 68.1 - 64.8 . oz. (2015 - 1915 ml)
10 T2® / T2-HPTM / T3 HD
TM
PURGING PROCEDURES
Due to 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 inefciency because its compression and expansion rate is higher than that of
the oil 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/trans-
mission is at the proper oil level. If it is not, ll
to the specications outlined on page 9.
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 at 3/4 to full throttle, slowly move the directional 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 closed and the
engine running, slowly move the directional
control in both forward and reverse
directions (5 to 6 times). Check the oil level,
and add oil as required after stopping
engine.
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.
T2® / T2-HPTM / T3 HDTM 11
RETURN TO NEUTRAL SETTING
WARNING
POTENTIAL FOR SERIOUS INJURY
Certain procedures require the vehicle engine
to be operated and the vehicle to be raised off
the ground. To prevent possible injury to the servicing technician and/or bystanders, insure the
vehicle is properly secured.
The return to neutral mechanism on the transaxle is designed to set the directional control
into a neutral position when the operator removes their foot from the foot control. Follow
the procedures below to properly adjust the
return to neutral mechanism on the transaxle:
1. Conrm the transaxle is in the operating mode
(bypass disengaged). Raise the vehicle’s drive
tires off the ground to allow free rotation.
NOTE: It may be necessary to remove the
drive tire from the axle hub to access
the linkage control and the transaxle
return arm.
2. Remove the Original Equipment Manufacturer’s (OEM’s) control linkage at the control
arm. Refer to Figure 4.
WARNING
Do not attempt any adjustments with the
engine running. Use extreme caution while
inspecting all vehicle linkage!
Follow all safety procedures outlined in the
vehicle owner’s manual.
3. Start the engine and increase the throttle to
full engine speed.
4. Check for axle rotation. If the axles do not
rotate, go to Step 5. If the axles rotate, go
to Step 6.
5. Stop the vehicle’s engine. Reattach and
adjust the OEM linkage according to
the OEM manual. Recheck according to
Step 3 and 4. Stop the vehicle engine.
Refer to Figure 4.
6. Note the axle directional movement. Stop
the vehicle engine. Loosen the lock down
screw (168) until the control arm (160) can
be rotated. Rotate the control arm in the
same direction of the wheel rotation in small
increments. Tighten the lock down screw.
Recheck according to steps 3 and 4. Refer
to Figure 4.
Spring (167)
Screw (41)
RTN Control Arm (160)
Lock Down Screw (168)
Bushing (165)
Scissor Arm (162)
RTN Neutral Arm (161)
Figure 4, Return to Neutral
12 T2® / T2-HPTM / T3 HD
TM
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