Hydro-Gear ZT-3600 Installation and operating manual

ZT-2800®/ZT-3100®/ZT-3200™/ZT-3400®
Integrated Zero-Turn Transaxle
Service and Repair Manual
BLN-52441
January 2018

ZT-2800®/ZT-3100®/ZT-3200TM/ZT-3400®iZT-2800®/ZT-3100®i
Foreword ...................................................... 1
Product Identication.................................... 1
Description and Operation............................ 2
Introduction................................................... 2
Hydraulic Schematic..................................... 3
External Features ...................................... 4-5
Technical Specications ............................... 6
Safety ........................................................... 7
Personal Safety ............................................ 7
Tool Safety.................................................... 7
Work Area Safety.......................................... 7
Servicing Safety............................................ 7
Troubleshooting............................................ 8
Service and Maintenance............................. 9
External Maintenance................................... 9
Service and Maintenance Procedures.......... 9
Fluids............................................................ 9
Fluid Volume and Level ................................ 9
Filter and Filter Guard................................. 10
Fluid Change Procedure............................. 11
Purging Procedures.................................... 12
Return To Neutral Setting ........................... 13
Return To Neutral Assembly ....................... 14
Control Arm Assembly ................................ 15
Parking Brake Adjustment .......................... 16
Parking Brake Assembly............................. 17
Brake Arm Assembly .................................. 18
Parking Brake Assembly..............................19
Hub Removal...............................................20
Tear Down and Reassembly........................21
How To Use This Manual.............................21
General Instructions .................................... 21
Tools ............................................................ 22
Torques........................................................ 22
Transaxle Removal...................................... 23
Fan and Pulley........................................ 23-25
Side Cover .................................................. 26
Bull, Pinion and Reduction Gears................ 27
Charge Pump .............................................. 28
Charge Pump Orientation.............................29
Input Shaft ................................................... 30
Bypass Arm ................................................. 31
Swashplate.................................................. 32
Center Section............................................. 33
Brake Assembly...................................... 34-35
Center Section Kit........................................ 36
Check Plugs & Seals................................... 37
Cylinder Blocks............................................ 37
Axle Shaft ............................................ 38-39
Assembly After Complete Tear Down .......... 40
Side Cover – Screw Tightening Sequence .. 41
How To Use Service Schematic .................. 42
Notes ........................................................... 43
ZT-2800® Exploded View & Parts List .... 44-45
ZT-3100® Exploded View & Parts List .... 44-45
ZT-3200TM Exploded View & Parts List... 44-45
ZT-3400® Exploded View & Parts List .... 46-47
Glossary Of Terms.................................. 48-49
Table Of Contents

ZT-2800®/ZT-3100®/ZT-3200TM/ZT-3400®1ZT-2800®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 ZT-2800®,
ZT-3100®, ZT-3200TM and ZT-3400® Integrated
Zero-Turn Transaxles.
Also included is a glossary of terms that are
frequently used throughout the industry and in
Hydro-Gear service publications. Understand-
ing 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 pre-
ferred methods of repair.
Internal repair procedures require that the
transaxle unit be removed from the vehicle.
This is not a certication, test or study guide for
a certication test. If a technician is interested in
certication, they should contact an agent rep-
resenting EETC (Equipment & Engine Training
Council) at [phone] or their Hydro-Gear
Central Service Distributor. Many distributors
will be hosting certication testing. These study
Figure 1, Conguration Label
PRODUCT IDENTIFICATION
The model and conguration of the ZT-2800, ZT-3100, ZT-3200 and ZT-3400 can be determined
from the label found on the transaxle.
HYDRO-GEAR
ZH-KCEE-1B8C-1BXX ZH-KCEE-1B8C-1BXX
5 186 B4 476 Assembled in USA
BOM Model Number
Year Built
Date (Julian- Day of year) Serial Number (unique for that model - for that day)
Type of Product and Build Information
Sales Drawing Number

2 ZT-2800®/ZT-3100®/ZT-3200TM/ZT-3400®
Both transaxles are fully ooded with oil. A
common external expansion tank assures the
drives’ cool, quiet operation. An external lter on
the transaxle allows for easy oil maintenance.
The ZT-2800 is designed for both charged and
uncharged product versions. In the uncharged
consumer vehicle drive, uid passes through
the lter by interaction of the positive head on
the uid from a properly elevated expansion
tank and the negative pressure created at the
pump inlet during piston operation.
Hydro-Gear’s patented charge conguration
is used in the ZT-3100, ZT-3200 and ZT-3400
version. Here, uid is drawn from the case and
through the lter and into a xed displacement
gerotor pump. Charge pump ow not used to
feed the low pressure side of the system is
passed over a charge relief valve and back into
the transaxle case.
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.
The ZT-2800, ZT-3100, ZT-3200 and ZT-3400
have an internal cog style parking brake. It is
essential to fully disengage the brake prior to
operation.
A cam style, block lifting bypass is utilized in
the ZT-2800, ZT-3100, ZT-3200 and ZT-3400 to
permit moving the vehicle for a short distance at
a maximum of 2 m.p.h. (3.2 Km/h) without start-
ing the engine. The brake must be disengaged
prior to actuating the bypass mechanism.
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.
Introduction
The purpose of this manual is to provide in-
formation useful in servicing the Hydro-Gear®
ZT-2800®, ZT-3100®, ZT-3200TM and ZT-3400®
Integrated Zero-Turn Transaxles. This manual
includes the general descriptions, hydraulic
schematics, technical specications, servic-
ing and troubleshooting procedures for both
transaxles.
Other than recommended oil and lter changes,
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 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 ZT-2800, ZT-3100, ZT-3200 and ZT-3400
are self contained units designed for the trans-
fer and control of power. They provide an in-
nitely variable speed range between zero and
maximum in both forward and reverse modes
of operation.
The ZT-2800, ZT-3200 and ZT-3100 transaxle
uses a variable displacement pump with a
maximum displacement of 10cc per revolu-
tion. The ZT-3400 transaxle uses a variable
displacement pump with a maximum displace-
ment of 12cc per revolution. Both transaxles
use a motor with a xed displacement of 16cc
per revolution. The variable displacement pump
features a trunnion mounted swashplate with
a direct-proportional displacement control. Re-
versing 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 compres-
sion springs.
DESCRIPTION AND OPERATION

ZT-2800®/ZT-3100®/ZT-3200TM/ZT-3400®3ZT-2800®3
Figure 3, Hydraulic Schematic Without Charge Pump (ZT-2800)
HYDRAULIC SCHEMATIC
Figure 2, Hydraulic Schematic With Charge Pump
Vent
Vent
Bypass
Motor Shaft
Motor
Pump
Filter
Charge Pump
Charge Relief
System Check Valves
Input Shaft
Case Reservoir
Motor Shaft
System Check Valves
Input Shaft
Filter
Pump Motor
Bypass
Case Reservoir