Service Manual

HY13-1521-M2/US Service Manual
General Information Series HB Hydrostatic Transmission
Introduction
The three-column format used in this Service Manual will help make it easy for you to service a UHT. Column 1
illustrates the procedure with photographs, Column 2 gives a brief key for each step, and Column 3 explains in
detail the procedure you should follow. Pay special attention to the notes, cautions, and warnings.
This manual contains troubleshooting information and checklists. With them you can diagnose a hydraulic
system problem without removing the entire assembly the checklists will help you to determine where the
problem may be.
Item numbers on the exploded view correspond with item numbers used throughout the Service Manual.
As you gain experience in servicing UHT Series, you may find that some information in this Service Manual
could be clearer and more complete. If so, let us know about it. Don’t try to second-guess the Service Manual; if
problems occur that you cannot solve, please contact your local OEM approved distributor. Servicing UHT Series
should be safe and productive.
DESIGN FEATURES
UHT

Large area cooling fins result in a cooler running system

Top housing and charge pump cover are sturdy, lightweight aluminum, excellent at
dispersing heat, resulting in an overall cooler system

Forged trunnion shaft increases shaft strength and lengthens pump life

Double caged thrust bearing improve lubrication and vibration absorption, thus
lengthening life of pump
Torqmotor

Roller vane to reduce friction and internal leakage and to maintain efficiency

A patented orbiting commutator system for less wear and longer life

A unique high-pressure shaft seal that eliminates the need for case drain

Manifold designed to improve operating efficiency

Roller vane and sealed commutation assure high volumetric efficiency and smooth low
speed operation
5
Parker Hannifin Corporation
Hydraulic Pump/Motor Division
Greeneville, Tennessee USA