Toro 41-20OE02, 41-20OE03, 51-12KE01, 51-12KE02, 51-16OE01 Service Manual

3/4/500 EATON 11 HYDROSTATIC TRANSMISSION - WH TRANSAXLE

Table of Contents – Page 1 of 2

FOREWORD

SPECIFICATIONS
TRANSMISSION:
TRANSAXLE:
MAINTENANCE:

GENERAL INFORMATION
TRANSMISSION DESCRIPTION AND IDENTIFICATION MARKINGS

PRINCIPLES OF OPERATION
TRANSMISSION S YST EM
SYSTEM OPERATION
TRANSMISSION OPERATION

TROUBLESHOOTING
PROBLEM DIAGNOSIS
GENERAL SYSTEM CHECKS
OIL SYSTEM
COOLING SYSTEM
ENGINE AND INPUT DRIVE
MOTION CONTROL LINKAGE
TRANSAXLE
HYDROSTATIC TRANSMISSION

TROUBLESHOOTING GUIDE
TRACTOR WILL NOT OPERATE IN EITHER DIRECTION
TRACTOR OPERATES IN BOTH DIRECTIONS, BUT LOSES POWER AS OIL
TRACTOR DOES NOT RETURN TO NEUTRAL.
HYDRAULIC LIFT SYSTEM DOES NOT OPERATE

ADJUSTMENTS
GENERAL
SINGLE ACTION BRAKE BAND ADJUSTMENT
DUAL ACTION BRAKE BAND ADJUSTMENT
MOTION CONTROL FRICTION
NEUTRAL

TESTING
SYSTEM PERFORMANC E
PRESSURE CHECKS
IMPLEMENT LIFT SYSTEM
CHARGE PRESSURE

3/4/500 EATON 11 HYDROSTATIC TRANSMISSION - WH TRANSAXLE

Table of Contents – Page 2 of 2

REPAIR OPERATIONS
GENERAL INFORMATION
HYDRAULIC HOSES - HYDRAULIC LIFT CONTROL VALVE
REMOVAL
INSTALLATION

TRANSMISSION
REMOVAL
PULLEY, GEAR AND CAM PLATE REMOVAL
INSTALLATION

TRANSAXLE
IN-VEHICLE SERVICE
CASE HALF SERVICE
INTERMEDIATE GEAR AND DIFFERENTIAL SERVICE
TRANSAXLE REASSE MB L Y

TRANSMISSION SYSTEM
REMOVAL
INSTALLATION
INTERNAL TRANSMISSION SERVICE
TRANSAXLE
TRANSAXLE
TRANSMISSION AND FILTER
TRANSMISSION AND FILTER
MOTION CONTROL, CLUTCH LINKAGE
MOTION CONTROL, CLUTCH LINKAGE
BRAKE AND LINKAGE SINGLE ACTION BRAKE BAND
BRAKE, AND LINKAGE SINGLE ACTION BRAKE BAND
BRAKE AND LINKAGE DUAL ACT I ON BRAK E BAND
BRAKE AND LINKAGE DUAL ACT I ON BRAK E BAND
EATON MODEL 11 TRANSMISSION

TRANSMISSION
REPAIR

MANUAL

Printed in

U.S.A.

1186

Form

1492-4205

PART

NO.

810243R

FOREWORD

This

service and repair manual has been compiled to provide
authorized Wheel Horse service personnel with
and techniques for servicing the

11

with Eaton Model

The

following Table of Contents lists all areas covered.

advisable to read all of the introductory sections first to gain a proper
understanding

The automatic transmission and transaxle are sophisticated

of machinery. Maintain strict cleanliness control during all stages

service and repair. Cover or cap all hose ends and fittings whenever
they are exposed. Even a small amount of dirt or other contamination

can severely damage the system.

This

1980-87

model tractors equipped with the Eaton Model

model year. It may

of

manual covers

hydrostatic transmission.

the Wheel Horse automatic transmission system.

the

be

Wheel

transmission system as

used to

the

the

proper procedures

Horse automatic transaxle

It

pieces

used

during

extent applicable for later

11

hydrostatic trans-

the

is

of

mission and Wheel Horse transaxle.

SPECIFICATIONS

TRANSMISSION:

Pump and Motor with Auxiliary Charge Pump.

Displacement:

Pump, Variable
Motor, Fixed. 2.09 cu. in./rev.

Speed (as used):

Input 3400
Output 0-1750

Torque Output (Max.)

Continuous 360
Intermittent

Operating Temperature:

Maximum Continuous 18OoF

Cooling:

8” Diameter Fan Plus Oil Flow From Charge Pump

Oil Filter (as used)

10

Micron, Full-flow, Spin-on Type

Charge Pump (3400

3.8 GPM Free Flow

1.4

GPM @ 700

TRANSAXLE:

Drive 8-pinion Differential and Double Reduction
Gears.

Gears and Shafts

Heat-Treated Steel

Bearings:

Ball
Needle

Case Halves and Hubs:

Cast Iron

Seals:

3, Double-lip, Spring-loaded

Ratios and Speeds:

Drive Belt Pulley Ratio
Overall Reduction Ratio
Axle Shaft Speed:

Tractor Speeds (approx.):

2

@

1750

Forward 0-7 MPH

Reverse 0-4.2 MPH

MAINTENANCE:

Oil Check Before Each Use
Replace

Oil

Initial After First
Periodic Once a Year, or After Every

of Use, Whichever Occurs

Oil Specification

1OW-30 or 1OW-40 Premium Motor Oil
Oil Capacity (approx.)
Oil Filter Wheel Horse 108335
Adjustments

Foot/Parking Brake
Motion Control Friction
Motion Control Neutral

Torque Value (Thread Sizes)

1/4-20 8

5/16-18 17-22 ft. Ibs.

3/8-16

1/2-135-13

Wheel Hub Set Screw 28-32

Eaton Model

0-1.10

11;

cu. in/rev.

Radial, Ball-piston

RMP

RPM

in.

Ibs.

540

in. Ibs.

RPM

Input)

PSI

Wheel Horse; Single-speed, with Uni-

6

1:l

15.64:l

RPM

Eaton Output

and Filter:

ft.

Ibs.

30-35

ft.

75-80 ft. Ibs.

100

Ibs.

112

Hours of

First

5

quarts

As

RPM

Use

Required

ft.

Ibs.

100

Hours

GENERAL INFORMATION

TRANSMISSION DESCRIPTION AND
IDENTIFICATION MARKINGS

NOTE

This

manual uses the terms transmission,

hydrostatic transmission] and hydrostatic unit"

11

to refer to the Eaton Model
Transmission. The term "transaxle"
refer to the assembly of intermediate gears,
differential and case halves, less hydrostatic
unit. "Transmission System" and "Automatic
Transmission System" are used to refer to en­tire drive train as an assembly, including en­gine, transmission, transaxle, hydraulic
system, and all related parts.

RADIAL BALL-PISTON MOTOR RADIAL BALL-PISTON PUMP

Hydrostatic

is

used to

lift

The Eaton Model
used by Wheel Horse,
charge pressure relief valve, forward and reverse
check :and acceleration valves, and vibration dampen­ing pistons. Transmission has a splined output shaft
and keyed input shaft, both of
by ball bearings. Besides making up for normal in­ternal transmission leakage, charge pump
operate tractor's hydraulic lift system. Charge pres­sure used to operate transmission
lated by a relief valve inside transmission. Implement

lift

system pressure

valve in hydraulic lift control valve.

Transmission
facturing date code, and direction of rotation. Rebuilt
units are also marked with a
angle used in photo, this information will appear

upide-down as- in Figure

11

hydrostatic transmission, as

is

equipped with an internal

which

is

700

PSI,

regulated by a relief

is

stamped with model number, manu-

"1".

are supported

is

30-90

If

viewed from

is

used to

PSI,

2.

regu-

CHECK VALVE

(TWO USED)

(CONTROLS TRANSMISSION OUTPUT

UP WHEN INSTALLED IN WHEEL

CONTROL SHAFT

SPEED AND DIRECTION

OF ROTATION-SHAFT POINTS

HORSE TRANSAXLE)

FIG.

1.

Internal Transmission Features

CHARGE

IMPLEMENT

SHAFT

CHARGE PUMP

PRESSURE

I

LIFT PRESSURE

30-90

PSI

700

PSI

-2-

FIG.

4.

left

Side

DIRECTION

MANUFACTURING DATE

PRINCIPLES

FIG.

OF

INPUT SHAFT

2.

Identification Markings

OF

OPERATION

TRANSMISSION SYSTEM

Major parts of Wheel Horse automatic transmission

system are identified in Figs.

FIG.

3.

3-5.

Right Side

5.

FIG.

SYSTEM

Transmission input shaft
by drive belt. Both charge pump and transmission
pump are driven by input shaft. Charge pump draws
oil from transaxle
make up for normal internal leakage, and provide a
cooling oil flow. Oil travels from outlet of charge
pump through a hydraulic hose, passes through open­center hydraulic lift valve and out to oil filter adapter
through another hose. After filtering,
through a metal line and into transmission.

Pump section of transmission controls volume and
direction of oil flow to motor section depending on
position of motion control linkage.

lever

is

increased to motor, making it go faster. Motor out­put shaft drives tractor axles through two reduction
gears and a differential assembly. Torque
ed in direct response to load; higher pump pressure
(torque)
creases.

For optimum performance engine should

ed

at full throttle, and never less than
Under high load conditions tractor should
using motion control lever, which will increase output
torque.
losses at slower transmission output speeds, and can

be

compared

mission to

System flow

OPERATION

to "supercharge "transmission

is

moved away from neutral position flow of

is

generated as resistance to movement in-

This

is

due to lower friction and pumping

to

the effect of shifting a manual trans-

a

lower gear.

is

illustrated in Figs. 6 and

Controls

is

driven at engine speed

oil

As

motion control

is

generat-

be

3/4

throttle.

be

7.

pump,

passes

oil

operat-

slowed

-3-

FIG.

6.

Oil

Flow

to

Hydraulic

Valve

Hydraulic lift circuit
pump. When lift control valve
Lower position, charge pump output
of hoses attached to lift cylinder. Other hose
nected through control valve to charge pressure hose
leading to oil filter, permitting bleed-off of oil on that

side

of lift cylinder's piston. Implement relief valve

located in control valve regulates

700

PSI.

to
into charge pressure hose leading to oil filter.

When this valve opens excess oil

is

also operated

is

by

charge

moved to Raise or

is

diverted to one

is

lift

system pressure

is

bled

con-

off

TRANSMISSION OPERATION

Flow diagrams show hydraulic circuits inside hydro­static unit and illustrate high and low pressure areas
during operation (Fig.

Pressurized oil from charge pump

30

between
inside hydrostatic unit. When valve opens excess oil
pressure

and

is

bled

TRANSAXLE

SUMP

8

and

9).

is

maintained

90

PSI

by charge relief valve located

back to transaxle sump through open

ball bearing on output shaft. Charge pump oil enters
transmission pump section,
speed, and "supercharges" it.

Operator controls transmission by moving control
shaft connected to cam ring within pump. With con­trol shaft in neutral, or its centered position, no flow

is

generated by pump and therefore motor portion

is

at rest.

When control shaft
ward" direction, cam ring in pump
er and pump ball-pistons create a flow of fluid. Posi­tion of control shaft/cam ring
and any flow rate
ring movement/maximum pump displacement.

Flow created by pump moves to fixed displacement
motor through internal passageways. Because motor

is

a fixed displacement unit, motor requires a specific

volume of fluid for it to make one complete revolution.

is

which

is

moved from neutral in "for-

possible up to maximum cam

is

turning at engine

is

moved

is

infinitely variable

off

cent-

RADIAL

(FIXED DISPLACEMENT)

BALL-PISTON

HYDRAULIC MOTOR

I

FORWARD/REVERSE

CHECK VALVES SHAFT

ACCELERATION

VALVES HYDRAULIC

HYDRAULIC LIFT CONTROL

VALVE, WITH

FIG.

700 PSI RELIEF VALVE

8.

Hydrostatic Transmission

MOTION

PUMP

I

I

Flow

RADIAL BALL-PISTON

HYDRAULIC PUMP

(VARIABLE DISPLACEMENT)

I

TRANSMISSION CHARGE PRESSURE

IMPLEMENT LIFT SYSTEM PRESSURE

Diagram

\

I

I

30-90

700 PSI

PSI

-5-

When control shaft

verse" direction, cam ring

side

posite

This

output shaft to rotate in opposite direction. Pump input
shaft always rotates in one direction, dictated by en­gine, while motor output shaft rotates in either direc­tion depending on direction of flow from pump.

Pump discharge flow
load) fluid. Flow returned from motor to pump
(or charge) pressure fluid.

Due to internal leakage, fluid being returned to in- Model
let side of pump from exhaust side of motor

than required by pump. To replace this needed fluid, sure. In operation they reduce control shaft vibration
check valves are located in each side of closed loop. and transmission noise.

The check valve located on low pressure side of pump
will open allowing fluid to enter loop, from charge
pump circuit, to make up leakage losses.

of pump and flow from pump is "reversed".

flow

is

directed to other side of motor causing its

is

moved from neutral to "re-

is

swung off center to op-

is

high pressure (dictated by

Internal acceleration valves are used in both for-

ward and reverse directions. These valves are spring

loaded to close "slowly" as pressure (load) increases.
These valves control rate of acceleration of motor out­put shaft, assist in providing a positive neutral, and
permit hand pushing tractor without operating engine.

In operation, as tractor's motion control lever
moved out of neutral, appropriate acceleration valve
bleeds off some of the high pressure oil before it closes.

This

is

low

is

less against cam ring and are controlled by system pres-

initial temporary pressure reduction results in

smoother tractor acceleration from a stand-still.

11

has two dampening pistons,

which

rest

is

PISTON

HIGH

LOW PRESSURE

PRESSURE

(30-90

TRANSAXLE SUMP

LIFT SYSTEM PRESSURE

FIG.

9.

System

Pressure

-6-

Schematic

PSI)

(700

PSI)

TROUBLESHOOTING

PROBLEM DIAGNOSIS

To save time and expense, a systematic approach

be

should
sion problem, starting with a thorough understanding
of how the system operates. Trouble symptoms should
be carefully noted and compared to Troubleshooting

Guide.

Whenever a problem occurs

ITEMS

1.

2.

3.

4.

5.

GENERAL

OIL SYSTEM

1.

2.

3.

4.

COOLING SYSTEM

I.

used when troubleshooting any transmis-

ALWAYS CHECK THESE

FIRST:

Transmission oil level and condition.
Motion control linkage.
Gaskets, seals, oil lines and fittings.
Transmission drive belt, pulleys and

transmission clutch.
Owner modifications to transmission system.

SYSTEM

Check

oil level when cold; overfilling transaxle
sump reduces the available expansion area and
may result in overflow at operating temperature.

A

low oil level will cause erratic operation and

may cause permanent damage to the hydro-

static unit. Replace leaking

Check

color of oil;
to black, overheating
milky white color, water contamination
dicated. Change transmission oil and filter be­fore further operation or tests.

Oil

filters that have not been replaced at specifi­ed interval can become clogged and cause
of power, overheating or non-operation.

Check

line fittings. Air can enter system without hav­ing an oil leak.

Cooling system consists of cooling fan, cast fins
in the aluminum transmission cover, and oil

circulated by the charge pump. Fan, cover fins,
and area surrounding transmission should be
kept clean for maximum cooling efficiency.
place a broken or cracked cooling fan.

tightness of all mounting bolts and

CHECKS

seals

if

natural color has changed

is

indicated.

and gaskets.

If

oil

is

is

loss

in-

oil

Re-

ENGINE AND INPUT DRIVE

1.

Check engine for correct no-load

2.

Run engine at load and

formance.

3.

Check drive belt, transmission clutch, pulleys,

keys

and keyways.

check

RPM.

for proper

per-

MOTION CONTROL LINKAGE

1.

Check

hardware. Replace worn parts to minimize free
movement.

2.

Check

full forward and reverse travel.

3.

Check

justments.

4.

Check

mission control shaft.

condition of all linkage and securing

for damage or binding parts that prevent

motion control friction and neutral ad-

condition of control arm, key and trans-

TRANSAXLE

1.

Roll tractor slowly and check for unusual noises
or seizing.

2.

Check

a

open transaxle and inspect gears, bearings, keys
and keyways.

for differential action and smooth oper-

This

ation of gear train.
rear

of

tractor and holding one wheel station-

ary while turning other wheel.

can be done by raising

If

necessary

HYDROSTATIC TRANSMISSION

1.

Rear wheels should "lock up"
at about walking speed.
of transmission condition.
the system are good and tractor's wheels do
not lock,
sive internal wear or an internal failure. Con­duct a charge pressure and power test.

it

is

likely that transmission has exces-

if

tractor

This

is

a rough

If

all other parts of

is

pushed

check

-7-

TROUBLESHOOTING GUIDE

TRACTOR WILL NOT OPERATE IN EITHER DIRECTION

IF

THE HYDRAULIC LIFT SYSTEM OPERATES NORMALLY

IS

THE TRANSMISSION CHARGE PUMP

CHECK MOTION

CONTROL LINKAGE

WORKING.

I

I

I

FAULTY FAULTY

I

PROPER LEVEL

CHECK CHARGE

PRESSURE

LOW

INSPECT FITTINGS,

LINES, HOSES, HYDRAULIC

LIFT VALVE FOR BLOCKAGE

FAULTY CLOGGED

REPAIR

REPLACE

OR

.OK-

ADJUST, REPAIR

OR

REPLACE

REPLACE HYDROSTATIC

TRANSMISSION

Possible Defects:

Acceleration Valve

Stuck Open

Both Check Valves

Stuck Open

High Internal

Leakage Due to

Wear/Contamination

Mechanical Failure

INSPECT

OIL FILTER

REPLACE

REPAIR

REPLACE

REPLACE HYDROSTATIC

TRANSMISSION

Possible Defects:

Charge Relief

Valve Stuck Open

Faulty Charge Pump*

High Internal

Leakage Due to

Wear/Contamination

Mechanical Failure

OR

'Charge Pump Can be Damaged by Improperly Set Implement Relief Valve. See "Charge Pressure Check"

-8-

TRACTOR OPERATES

POWER AS OIL BECOMES HOT.

TRANSMISSION OVERHEATS

CHECK OIL

CONDITION

IN

BOTH DIRECTIONS, BUT LOSES

COOLING FINS

LOW SIGNS OF FAULTY

I

PROPER LEVEL AND FILTER CLEAN TRANS.

CHECK CHARGE MAKE SYSTEM REPLACE HYDROSTATIC

INSPECT FITTINGS, LINES,

HOSES, HYDRAULIC LIFT

VALVE FOR PARTIAL

BLOCKAGE

OVERHEATING DlRTY OVERLOADED

OR

WATER

PERFORMANCE TEST TRANSMISSION

TO CONFIRM LOW

POWER CONDITION

INSPECT

OIL FILTER

CLOGGED

TRACTOR

I I

MAINTAIN FULL

ENGINE RPM,

REDUCE SPEED

AND LOAD

Probable Defect:

High Internal

Leakage Due to

Wear/Contamination

REPLACE HYDROSTATIC

TRANSMISSION

Possible Defects:

Charge Relief Valve

Leaking

Faulty Charge Pump*

Internal Leakage

Due

to

Wear/Contamination

*Charge Pump Can be Damaged by Improperly Set Implement Relief Valve. See “Charge Pressure Check”.

-9-