Cub Cadet ZD User Manual
EZT
®
Integrated Zero-Turn Transaxle
Service and Repair Manual
(ZC & ZD Models)
BLN-52622
July 2010
TABLE OF CONTENTS
Section Page
Foreword .............................................................................................................................. 1
Description and Operation ................................................................................................. 2
Introduction .................................................................................................................................................. 2
General Description ..................................................................................................................................... 2
Hydraulic Schematic .................................................................................................................................... 3
External Features -EZT® ......................................................................................................................... 4
Technical Specications ............................................................................................................................... 5
Product Identication ................................................................................................................................... 5
Safety .................................................................................................................................... 6
Personal Safety ............................................................................................................................................ 6
Tool Safety ................................................................................................................................................... 6
Work Area Safety ......................................................................................................................................... 6
Servicing Safety ........................................................................................................................................... 6
Troubleshooting .................................................................................................................. 7
Service and Maintenance.................................................................................................... 8
External Maintenance .................................................................................................................................. 8
Service and Maintenance Procedures ......................................................................................................... 8
Fluids ........................................................................................................................................................... 8
Fluid Volume and Level ................................................................................................................................ 8
Fluid Change Procedure .............................................................................................................................. 9
Purging Procedures ................................................................................................................................... 10
Return to Neutral Setting ............................................................................................................................11
Repair ................................................................................................................................. 12
How To Use This Section ........................................................................................................................... 12
General Instructions ................................................................................................................................... 12
Transaxle Removal .................................................................................................................................... 12
Limited Disassembly .................................................................................................................................. 12
Tools and Torques ...................................................................................................................................... 13
Hub Replacement ................................................................................................................................. 14-15
Control Arm and Bypass Arm ..................................................................................................................... 16
Seal Kit Replacement ................................................................................................................................ 17
Cog Brake Assembly .................................................................................................................................. 18
Disc Brake Assembly ................................................................................................................................. 19
Side Cover ................................................................................................................................................ 20
Axle Shaft, Reduction Gears and Expansion Plate .................................................................................... 21
Motor Shaft ................................................................................................................................................ 22
Input Shaft and Bypass Rod ...................................................................................................................... 23
Hydraulic Components .......................................................................................................................... 24-28
Transaxle Installation ................................................................................................................................. 28
Assembly After a Complete Teardown ....................................................................................................... 29
Sealant Application ........................................................................................................... 30
Parts List ...................................................................................................................... 32, 33
Glossary of Terms ....................................................................................................... 34, 35
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 EZT
®
Inte-
grated Zero-Turn Transaxle.
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.
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 OPEESA (Outdoor Power Equipment and Engine Service Association) at (860)
767-1770 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 call our Customer Service Department at (217) 728-2581.
®
1
EZT
SECTION 1. DESCRIPTION AND OPERATION
INTRODUCTION
The purpose of this manual is to provide information useful in servicing the Hydro-Gear
®
Integrated Zero-Turn Transaxle (EZT®). This manual includes the EZT’s general descriptions,
hydraulic schematics, 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 EZT is a self contained unit designed for
the transfer and control of power. It provides an
innitely 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 10cc 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
nosed pistons which are held against a thrust
race by internal compression springs.
The EZT has 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 make-up ow of the uid to the
low pressure side of the loop.
A cam style, block lifting bypass is utilized in
the EZT 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.
Figure 1. Hydraulic Schematic
2 EZT
®
EZT® HYDRAULIC FLOW SCHEMATIC
Figure 2. Hydraulic Flow Illustration
HYDRAULIC SCHEMATIC
Figure 2 provides an illustration of the hydraulic
oil circuit. The oil supply for the hydraulic system of the EZT® 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 pistons 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 mo-
tor 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 pump 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 upon
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 EZT has a mechanical
lever which lifts the motor block off of the center
section running surface. This allows oil ow
from the cylinder blocks to be discharged.
®
3
EZT
EXTERNAL FEATURES EZT
MAIN HOUSING
®
AXLE SHAFT
BYPASS ARM
SIDE COVER
FILL PORT
BRAKE ARM
INPUT SHAFT
CONTROL ARM
COG BRAKE DISC
FAN
PULLEY
AXLE SHAFT
4 EZT
®
TECHNICAL SPECIFICATIONS
Technical specications for the EZT® are listed in Table 1.
Table 1. Technical Specications
Input Speeds Weight of Unit
Maximum: 3000 RPM 29 lbs. (13 Kg)
Minimum: 1800 RPM
Table 2. EZT Component Options
Component Component Options
Axle Shaft Diameter and End Options: 1˝ Flange 1˝ DD
Brake Location: Inboard Outboard
Brake Type: Cog Disc
Control Arm Location: Inboard Outboard
Control Arrangements: Standard Control Arm RTN (scissor style)
Overall Transaxle Reduction: 19.2:1 21.2:1
PRODUCT IDENTIFICATION
The model and conguration of the EZT can be determined from the label shown in Figure 3.
Figure 3. Conguration Label
®
5
EZT
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 EZT
the safety precautions described in this
section.
®
, fully read and understand
PERSONAL SAFETY
Certain safety precautions must be observed
while servicing or repairing the EZT. This section 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 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.
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 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.
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.
6 EZT
®
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!
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 pump
is malfunctioning. Table 3 below provides a
In many cases, problems with the EZT® are not
Follow all safety procedures outlined in
the vehicle owner’s manual.
Table 3. EZT Troubleshooting Checklist
troubleshooting checklist to help determine the
cause of operational problems.
Possible Cause Corrective Action
UNIT OPERATES IN ONE DIRECTION ONLY
Control linkage bent or out of adjustment Repair or replace linkage, Page 8
Drive belt slipping or pulley damaged Repair or replace drive belt or pulley, Page 8
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 8 and 11
Bypass assembly sticking Repair or replace bypass, Page 21
UNIT IS NOISY
Oil level low or contaminated oil Fill to proper level or change oil, Page 9
Excessive loading Reduce vehicle loading, Page 8
Loose parts Repair or replace loose parts
Bypass assembly sticking Repair or replace linkage
Air trapped in hydraulic system Purge hydraulic system, Page 10
UNIT HAS NO/LOW POWER
Engine speed low Adjust to correct setting
Control linkage bent or out of adjustment Repair or replace linkage, Page 8
Drive belt slipping or pulley damaged Repair or replace drive belt or pulley, Page 8
Oil level low or contaminated oil Fill to proper level or change oil, Page 9
Excessive loading Reduce vehicle loading, Page 8
Bypass assembly sticking Repair or replace linkage
Air trapped in hydraulic system Purge hydraulic system, Page 10
UNIT IS OPERATING HOT
Debris buildup around transaxle
Cooling fan damaged Repair or replace cooling fan
Oil level low or contaminated oil Fill to proper level or change oil, Page 9
Excessive loading Reduce vehicle loading, Page 8
Air trapped in hydraulic system Purge hydraulic system, Page 10
Clean off debris, Pages 2 and 8
TRANSAXLE LEAKS OIL
Damaged seals, housing, or gaskets Replace damaged component
Air trapped in hydraulic system Purge hydraulic system, Page 10
®
7
EZT
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 EZT®
should include the following:
1. Check the vehicle operator’s manual for
the recommended load ratings. Insure
that the current application does not
exceed load rating.
2. Check oil level in accordance with Figure 4
Page 9.
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.
4. Inspect the vehicle control linkage to the
directional control arm on the transaxle. Also
insure that the control arm is securely fastened to the trunnion arm of the transaxle.
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
20W50 engine oil has been selected for use
by the factory and is recommended for normal
operating procedures.
FLUID VOLUME AND LEVEL
Fluid volume information is provided in Table
4.
Certain situations may require additional uid
to be added or even replaced. Refer to Page 4
for the proper ll port location.
Fill the EZT so the oil level is .75”-1.50” (19-38
mm) below the oil ll port.
Recheck the uid level once the unit has been
operated for approximately 1 minute.
Purging will be required. Refer to the purging
procedures on Page 10.
5. Inspect the bypass mechanism on the transaxle and the vehicle linkage to insure that
both actuate and release fully.
SERVICE AND MAINTENANCE
PROCEDURES
Some of the service procedures presented on
the following pages can be performed while
the EZT 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. The
unit should be thoroughly cleaned before any
service procedures are performed.
8 EZT
®
FLUID CHANGE
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.
NOTE: If removing the wheel from the
transaxle, do so by removing the four (4)
lug nuts. Do not remove the axle/hub nut.
2. Clean the oil ll port area of any debris.
3. Remove the oil ll port tting.
Table 4. Fluid Volumes for the EZT
Fluid Description
4. Position the transaxle so the oil will drain
completely out of the housing.
5. Fill the transaxle at the oil ll port according
to Figure 4.
6. Install the oil ll port tting.
7. Purging will be required. Refer to the purging
procedures on Page 10.
8. Recheck the uid level once the unit has
been operated for approximately 1 minute.
®
Volume
20W50 engine oil
OIL LEVEL
52.4 . oz. (1550 ml) to 55.8 . oz. (1650 ml)
TOP OF FILL PORT
0.75” - 1.50” (19-38mm) depth
at 50°-100°F (10°-38°C)
Figure 4. Fluid Level and Fill Port
®
9
EZT
Loading...