Danfoss Integrated Hydrostatic Transaxle Service guide

Brand: Danfoss

Model: Integrated Hydrostatic Transaxle

Type: Service guide

IHT-M15

Integrated

Hydrostatic Transaxle

Service Manual

IHT-M15 Introduction 1

1. Introduction

1.1 Use of This Manual

This manual includes information for the normal

operation, maintenance, and servicing of the IHT-

M15 integrated hydrostatic transaxle. The manual

includes the description of the unit and its individual

components, troubleshooting information, adjustment

instructions, and minor repair procedures. Unit war-

ranty obligations should not be affected if mainte-

nance, adjustment, and minor repairs are performed

according to the procedures described in this manual.

The service and adjustment activities described in

this manual can usually be performed without remov-

ing the unit from the vehicle. However, adequate

access to the part of the unit involved must be

1.2 Safety Precautions

Loss of Hydrostatic Braking Ability

WARNING

The loss of hydrostatic drive line power in any

mode of operation (e.g. acceleration, decelera-

tion or "neutral" mode) may cause a loss of

hydrostatic braking capacity. A braking sys-

tem which is independent of the hydrostatic

transmission must, therefore, be provided

which is adequate to stop and hold the system

should the condition develop.

Disable Work Function

WARNING

Certain service procedures require the vehicle/

machine to be disabled (wheels raised off the

ground, work function disconnected, etc.) while

performing them in order to prevent injury to

the technician and bystanders.

Fluid Under High Pressure

WARNING

Use caution when dealing with hydraulic fluid

under pressure. Escaping hydraulic fluid un-

der pressure can have sufficient force to pen-

etrate your skin causing serious injury. This

fluid may also be hot enough to burn. Serious

infection or reactions can develop if proper

medical treatment is not administered immedi-

ately.

Flammable Cleaning Solvents

WARNING

Some cleaning solvents are flammable. To

avoid possible fire, do not use cleaning sol-

vents in an area where a source of ignition may

be present.

The procedures herein should be performed by trained personnel only. Observe the following safety precautions

when using and servicing hydrostatic products.

F100203

available, and the unit must be thoroughly cleaned

before beginning maintenance, adjustment, or repair

activities. Since dirt and contamination are the great-

est enemies of any type of hydraulic equipment,

cleanliness requirements must be strictly adhered to.

This is especially important when changing the sys-

tem filter and during adjustment and repair activities.

A worldwide network of Sauer-Danfoss Autho-

rized Service Centers is available should repairs be

needed. Contact any Sauer-Danfoss Authorized

Service Center for details. A list of all Service Centers

can be found in bulletin BLN-2-40527, or in brochure

SAW (Ident. No. 698266).

IHT-M15 Introduction 1

Table of Contents

1. Introduction ................................................................................................................................................2

1.1 Use of This Manual ...................................................................................................................................2

1.2 Safety Precautions ....................................................................................................................................2

2. Functional Description ..............................................................................................................................4

2.1 Component Location .................................................................................................................................5

2.2 Hydraulic Circuit and Components ...........................................................................................................8

2.3 Mechanical Drive Components ............................................................................................................... 11

2.4 Control Features ..................................................................................................................................... 12

3. Technical Specifications .........................................................................................................................14

4. Tools and Pressure Measurement ..........................................................................................................15

4.1 Required Tools ........................................................................................................................................ 15

4.2 Pressure Gauge Installation ....................................................................................................................15

5. Start-up, Fluids, and Filter.......................................................................................................................16

5.1 Fluids Specification .................................................................................................................................16

5.2 Start-up Procedure ..................................................................................................................................16

5.3 Fluid and Filter Change ...........................................................................................................................17

6. Inspections and Adjustments .................................................................................................................18

6.1 Charge Pressure Priority Valve Inspection .............................................................................................18

6.2 Implement Relief Valve Adjustment ........................................................................................................19

6.3 Neutral Return Mechanism Inspection .................................................................................................... 21

6.4 Pump Neutral Start Switch (NSS) Adjustment ........................................................................................ 23

6.5 Electrohydraulic Control Inspection ........................................................................................................26

6.6 Speed Sensor Adjustment ...................................................................................................................... 27

7. Minor Repairs ...........................................................................................................................................28

7.1 Plug / Fitting Torques ..............................................................................................................................28

7.2 Shaft Seals..............................................................................................................................................29

7.3 Neutral Start Switches ............................................................................................................................31

7.4 Filter ........................................................................................................................................................32

7.5 Dip Stick, Fill Tube, Breather, and Fill Level Plug ...................................................................................32

7.6 PTO Auxiliary Mounting Pads ................................................................................................................. 33

7.7 System Check / High Pressure Relief Valves (SCRs) ............................................................................34

7.8 Easy-Ride Valves ....................................................................................................................................35

7.9 Charge Pressure Priority Valve ............................................................................................................... 36

7.10 Implement Circuit Relief Valve ................................................................................................................37

7.11 Charge / Implement Pump ...................................................................................................................... 38

7.12 Neutral Return Mechanism .....................................................................................................................39

7.13 2-Position Electrohydraulic Control and Bearing Carriers for Variable Motor ......................................... 40

8. Exploded View Parts Drawings ............................................................................................................... 42

8.1 Hydraulic Center Section Minor Repair Parts .........................................................................................42

8.2 Hydraulic Housing Minor Repair Parts and Name Plate ......................................................................... 43

8.3 Variable Motor Controls Minor Repair Parts ........................................................................................... 44

8.4 Front Section Minor Repair Parts ...........................................................................................................45

8.5 Parts Description..................................................................................................................................... 46

IHT-M15 Functional Description 2

The IHT-M15 integrated transaxle is designed to

provide a complete propel, PTO, and hydraulic pack-

age for lower power off-road vehicles. It incorporates

a complete hydrostatic transmission, mechanical

gearbox, drive axle with differential, PTO system with

electromagnetic clutch/brake, and hydraulic pump

with reservoir and filter in a single unit.

An axial piston design pump and motor are utilized in

the hydrostatic transmission. The variable displace-

ment pump incorporates a tiltable trunnion swash-

plate allowing direct displacement control. One of two

motor types is used. The fixed displacement motor

(MF) has a fixed swashplate. The variable displace-

ment motor (MV) option utilizes an electrically oper-

ated, 2-position hydraulic control system.

Power is routed from the hydrostatic transmission

through either a single speed or a 2-speed mechani-

cal gearbox to the differential and drive axles. An

output shaft for a mechanical 4-wheel drive steerable

axle may be provided, and a companion steerable

drive axle is available.

The electromagnetic PTO clutch/brake operates in

oil to provide long life and smooth operation. A shaft

output for mechanical PTO drives may be provided,

as well as a drive for a PTO hydraulic pump.

A built-in hydraulic gear pump provides charge oil

pressure for the hydrostatic transmission through a

unique pressure priority valve. Flow from this pump is

available for auxiliary hydraulic services via an imple-

ment circuit. The pump utilizes the transaxle housing

as a reservoir. A suction-type filter is provided on the

transaxle housing.

2. Functional Description

IHT-M15

WITH FIXED MOTOR

IHT-M15

WITH VARIABLE MOTOR

Rear

Right

Left

Front

IHT-M15 with Different Motor Options - Orientation Used in This Manual

Note: Actual orientation will vary with application. This orientation applies to applications with the unit in the

front axle position.

E100032

IHT-M15 Functional Description 2

Front Cover

Axle

Electrohydraulic

Control

Gear Housing

Hydraulic

Housing

Hydraulic Center

Section

Axle

2.1 Component Location

The IHT-M15 is made up of several major assembly

sections. The hydraulic center section contains most

of the porting and pressure control mechanisms. The

hydraulic housing contains the pump and the motor.

The gear housing contains the gearing between the

input and output shafts. The front cover closes the

housing and mounts the auxiliary pads.

The assemblies are shown for reference only. Ser-

vice activities do not involve the disassembly of the

major sections.

CAUTION

Disassembly of the major sections is not a

service activity. Any disassembly of the major

sections will void the unit warranty. Incorrect

assembly of the interior components can se-

verely damage the unit.

The following two pages display outline drawings

showing the location of the IHT-M15 components

covered in this service manual.

Major Assembly Sections

E100049

IHT-M15 Functional Description 2

IHT-M15 Outlines Showing Features (Fixed Motor Unit Shown) (A)

Implement Circuit Relief Valve

Range Control Neutral Start Switch

Pump Control Shaft

Range Control Shaft

Implement Pump

Integral Filter

TOP VIEW

Input Shaft

4WD Shaft

Charge Pressure Valve

System Check / High

Pressure Relief Valves

Easy-Ride Valves

Variable Motor Control

(not shown)

REAR VIEW

Fill Tube

PTO Clutch Connector

Dip Stick

Speed Sensor

(not shown)

Implement Return

Auxiliary Pad

(no pad shown)

Oil Drain

Fill Level Plug

FRONT VIEW

Breather Vent

P100111

P100112

P100113

IHT-M15 Functional Description 2

Implement

Circuit Port

Charge Pressure

Priority Valve

Pump Neutral

Start Switch

Neutral Return

Mechanism

LEFT SIDE VIEW

System Check / High

Pressure Relief Valves

IHT-M15 Outlines Showing Features (Fixed Motor Unit Shown) (B)

Control Port

(for Variable Motor)

Pump Control Shaft

PTO Shaft

Range Control Neutral Start Switch

Range Control Shaft

Auxiliary Pad

(no pad shown)

RIGHT SIDE VIEW

System Check / High

Pressure Relief Valve

Speed Sensor

Port

P100114

P100115

IHT-M15 Functional Description 2

Basic Closed Circuit

The main ports of the pump are connected internally

in the hydraulic center section to the main ports of the

motor. Fluid flows, in either direction, from the pump

to the motor then back to the pump in this closed

circuit. Either of the hydraulic passages can be under

high pressure. The position of the pump swashplate

determines which passage is high pressure as well

as the direction and amount of fluid flow.

2.2 Hydraulic Circuit and Components

Input

(MF)

Case

Output

Flow (Bidirectional)

Reservoir

(MV)

Inlet

Filter

Implement Circuit

Relief Valve

Charge /

Implement

Pump

25cc Fixed

or Variable

Motor

Charge

Pressure

Priority Valve

15cc

Variable

Pump

Reservoir

Open Center Valve(s) for

Steering / Implement Circuit(s)

(Customer Supplied)

Recommended Return Filter

(Customer Supplied)

Heat Exchanger

(Customer Supplied)

IHTÐM15 Hydraulic and

Hydrostatic Components

(Included in IHTÐM15)

Complete Hydraulic Circuit Schematic for IHT-M15

P100116

P100117

Basic Hydraulic Closed Circuit Schematic

IHT-M15 Functional Description 2

Inlet

Filter

Implement Circuit

Relief Valve

Charge /

Implement

Pump

Charge

Pressure

Priority Valve

Reservoir

Open Center Valve(s) For

Steering / Implement Circuit(s)

(Customer Supplied)

Recommended

Return Filter

(Customer Supplied)

Heat Exchanger

(Customer Supplied)

System

Check Valves

System Circuit

High Pressure

System Circuit

Low Pressure

Charge / Implement Hydraulic Pump

A fixed displacement (gear type) pump is installed on

the hydraulic housing and is driven off the closed

circuit pump shaft. The pump supplies cool fluid to the

system, keeps the system charged, supplies fluid to

operate the motor control system, and provides flow

to the auxiliary hydraulic circuits. Charge pressure is

regulated by a pressure priority valve.

Filter

The pump draws fluid from the transaxle housing. An

integral inlet filter is provided to insure that only clean

fluid enters the system.

Heat Exchanger

A heat exchanger, with a bypass valve, is required to

cool the return flow from auxiliary hydraulic circuit

fluid before it returns to the transaxle housing.

Charge Pressure Priority Valve

Charge pressure is controlled by a priority pressure

valve which directs flow from the charge /implement

hydraulic pump. Priority flow from this valve is di-

rected to the charge circuit. Once the desired charge

pressure is reached, excess flow is directed to the

implement circuit.

When pressure in the implement circuit increases,

this valve acts as a pressure reducing valve to main-

tain the charge pressure at a constant level.

Implement Circuit Relief Valve

A relief valve is provided to protect the implement

circuit from overload. The setting of this valve is

adjustable and set at the factory.

Poppet

Spring

O-Ring

Plug

Seal Lock Nut

Adjusting Screw

Plug

O-Ring

Spring Charge Pressure

Priority Valve Spool

Charge / Implement Circuit Schematic

Cross-Section of Implement Relief Valve

in IHT-M15 Housing

Cross-Section of Charge Pressure Priority Valve

in IHT-M15 Housing

P100118

P100119

P100120

IHT-M15 Functional Description 2

System Relief Valves (SCRs)

Combination system check / high pressure relief

valves are provided in the hydraulic center section for

closed loop overload protection. These cartridge type

relief valves are factory set, and are not field adjust-

able. Changing the maximum system pressure can

be accomplished by installing different cartridges

with the desired setting.

Easy-Ride Valves

The Easy-Ride valves work to reduce the rate of

change in acceleration (ÒjerkinessÓ) of the vehicle by

limiting the rate of pressure rise in the closed loop.

These valves permit flow from the high to the low

pressure side of the loop (through the charge circuit)

when loop pressure increases suddenly.

Each Easy-Ride valve consists of a poppet-piston,

sleeve assembly, spring, and plug, which are in-

stalled in the hydraulic center section. The poppet-

piston and its seat form a valve to close off the

passage between one side of the closed loop and the

charge pressure passage. The spring pre-loads the

sleeve assembly and holds the poppet-piston closed

against its seat in the end cap when loop pressure is

low.

"Easy-Ride"

Valves

System Check /

High Pressure Relief

Valves

Charge

Pressure

System Loop, High or Low Side

Plug

O-Ring

Cone

Spring

System Check /

High Pressure Relief Valve

From Closed Loop

(System Pressure)

To Charge Checks

(Charge Pressure)

Poppet-Piston

Sleeve Assembly

Spring

Plug

Cross-Section of Easy-Ride Valve

in IHT-M15 Housing

Cross-Section of System Relief Valves

in IHT-M15 Housing

Schematic of System Relief and Easy-Ride Valves

P100121

P100123

P100122

IHT-M15 Functional Description 2

2.3 Mechanical Drive Components

PTO System

Drive Axle

Mechanical Reduction Drive

Helical gears are used for quiet operation. The pinion

for the mechanical drive reduction is splined to the

hydrostatic motor shaft when the gear changer cou-

pling is engaged via a shift yoke. The gear changer

can be shifted to a neutral position-disengaging the

final drive. A two speed option is available.

Differential and Drive Axle

Spiral bevel gears are used for final vehicle drive

reduction. A forging is used for a single piece axle

design with double row tapered roller bearings.

PTO System

Helical gears are used for quiet operation to drive the

PTO system. An electromagnetic clutch/brake when

energized engages the PTO system. In the non-

energized state springs load the brake discs to stop

the PTO system.

PTO Auxiliary Pads

Auxiliary pads allow the PTO to be mounted with an

auxiliary gear pump. Different pads allow for different

mating standards.

Drive Shaft

Electromagnetic

Clutch/Brake

PTO Auxiliary Pad Option

Mechanical PTO Shaft

Input Shaft

Hydrostatic Pump and Motor

4WD Output Shaft

Axle Shaft

Disc Brake (Option)

Axle Shaft

Low Range

High Range (Option)

Electromagnetic PTO Clutch / Brake

Auxiliary Flange Shaft

PTO Output Shaft

Mechanical Schematic for IHT-M15

Motor Shaft

Spiral Bevel

Drive Shaft

Low Range

High Range

Range Control Collar

4WD Shaft

Pump

Motor

P100124

P100125

P100126

P100127

IHT-M15 Functional Description 2

Variable Motor 2-Position Electrohydraulic

Control

This control utilizes an electric solenoid operated 2-

position hydraulic valve to port charge pressure to

either of the motor displacement control pistons. The

motor is normally held at its maximum displacement.

Energizing the solenoid will cause the motor to go to

its minimum displacement.

Pump Neutral Return Mechanism

The pump neutral return mechanism maintains and

returns the pump swashplate to neutral position. The

mechanism requires that the displacement control

linkage contain less than 2 Nm (20 in

•

lbf) of friction.

If the neutral return mechanism is off-center, it can be

adjusted as in Sec. 6.3.

Control Piston

Variable Motor

Control Housing

Motor Trunnion

Control Arm

Solenoid

Pump Swashplate

Trunnion

Neutral Return

Assembly

2.4 Control Features

Pump Neutral Return Mechanism

Cross-Section of Variable Motor and

Electrohydraulic Control

in IHT-M15 Housing

P100129

P100128

IHT-M15 Functional Description 2

Neutral Start Switches (NSS)

The IHT-M15 may have neutral start switches to

ensure engine engagement does not occur with the

unit out of neutral.

The pump neutral start switch provides a means to

prevent the vehicle engine from starting while the

pump swashplate is in a position which would place

the pump "in-stroke" in either the "forward" or "re-

verse" direction.

When the pump swashplate trunnion is in its "neutral"

position (zero displacement), the inner end of the

switch pin moves into a slot on an eccentric cam

which is linked to the swashplate via a lever. This

allows the spring-loaded NSS to close, completing

the electrical starting circuit for the vehicle engine.

When the swashplate shaft is NOT in its "neutral"

position, the eccentric cam moves the switch pin out

of the slot. This forces the NSS to open, breaking the

electrical starting circuit for the vehicle engine.

The range control neutral start switch works in a

similar manner. It permits the engine to start only

when the range control is set at neutral. This prevents

the drive function from being suddenly engaged at

start-up.

Speed Sensor

An optional speed sensor can be installed to provide

motor speed information. The sensor reads a mag-

netic ring on the motor cylinder.

NSS

Location of Neutral Start Switches

and Speed Sensor Port

Cross Section of Pump Neutral Start Switch

in Neutral Return Mechanism

(Range Control NSS Similar)

Pump Neutral

Start Switch

LEFT SIDE VIEW

Range Control

Neutral Start Switch

RIGHT SIDE VIEW

Speed Sensor

Port

P100130

P100131

IHT-M15 Technical Specifications 3

3. Technical Specifications

Maximum Input Power

26 kW (35 horsepower)

Maximum Weight on the Axle

Up to 1600 kg (3520 lb)

Will vary by application.

Input Speed

Designed for 2600 to 3600 rpm rated engines

Output Speeds

Single or two-speed final ratios are available with

fixed or variable motor inputs.

Pump Displacement

15 cm

/rev

Motor Displacement

25 cm

/rev fixed or maximum variable

13 cm

/rev minimum variable

Charge Pump Displacement

6.4 cm

/rev (0.39 in

/rev)

Maximum Axle Output Torque

2170 Nm (1600 ft

•

lbf)

Rated Axle Output Torque

875 Nm (650 ft

•

lbf)

Will vary by application.

Caliper Disc Brake Capacity (Option)

Contact Sauer-Sundstrand for options and speci-

fications.

PTO and Auxiliary Pad Speeds

Up to 2000 rpm.

Exact speed will vary depending on engine speed

and available ratios.

PTO Torque

Maximum: 107 Nm (945 in

•

lbf)

Continuous: 85 Nm (756 in

•

lbf)

Continuous torque capacity will vary by applica-

tion.

Electromagnetic PTO Clutch Brake

Performance

Brake torque (static): 30 Nm (22 ft

•

lbf)

Three second stop time from 2000 rpm: 2.8 Nm

(6.8 lbf

•

) free inertia

Hydraulic Implement Circuit

Implement flow: 11 l/min (3 gpm) at 50 bar (725 psi)

Implement relief valve setting: 70 bar (1000 psi)

standard - may be other setting tailored to applica-

tion (see Sec. 6.2).

Reservoir Capacity

Integral reservoir in housing holds approximately

11 liters (3 U.S. gallons), depending upon axle

width

Unit Weight

117 kg (258 lb)

IHT-M15 Tools and Pressure Measurement 4

4. Tools and Pressure Measurement

4.1 Required Tools

The service procedures described in this manual for

the IHT-M15 transaxle can be performed using com-

mon mechanic's tools.

4.2 Pressure Gauge Installation

Pressure gauges should be calibrated frequently to

ensure accuracy. Snubbers are recommended to

protect pressure gauges.

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Pressure gauges are used to measure pressure at

various points in the hydraulic circuit. The IHT-M15

has dedicated gauge ports for system pressure and

charge pressure. Implement circuit pressure can be

measured by teeing into the implement circuit hose

that exits the implement outlet port. Case pressure is

maintained at atmospheric pressure through the

breather vent.

NOTE: Implement circuit pressure can be mea-

sured directly from the implement circuit outlet

port. However, as this forces flow through the

implement circuit relief valve, heat will generate

quickly. The IHT-M15 should not be run for more

than a short period in this way.

WARNING

Fluid under high pressure. Do not remove or

install gauges or plugs when the engine is on.

Charge Pressure

Gauge Port "M3"

System Pressure

Gauge Ports

"M1" and "M2"

TOP VIEW

Auxiliary Charge Pressure

Gauge Port M6 (Fixed Motor Only)

RIGHT SIDE VIEW

Implement

Circuit Port

LEFT SIDE VIEW

For proper hose torques, see Sec. 7.1.

Location of Gauge Ports

P100132

P100133

IHT-M15 Start-Up, Fluids, and Filter 5

This start-up procedure should always be followed

when starting-up a new IHT-M15 installation.

WARNING

The following procedure requires the vehicle

to be disabled (wheels raised off the ground or

other precautions taken) while performing the

procedure in order to prevent injury to the

technician and bystanders. Take necessary

safety precautions before moving the vehicle/

machine.

Make certain all system components (reservoir, hoses,

valves, fittings, heat exchanger, etc.) are clean prior

to filling with fluid.

Fill the housing reservoir with recommended fluid

which should be passed through a 10 micron (nomi-

nal, no bypass) filter prior to entering the reservoir.

The use of contaminated fluid will cause damage to

the components.

When the housing reservoir is filled to the proper level

the filter will be full of fluid. Check that the inlet filter

cartridge is properly tightened to avoid leakage.

Install a 50 bar (500 psi) pressure gauge in the charge

pressure gauge port to monitor charge pressure

during start-up.

Place the range control in its neutral position. It is

recommended that the external control input linkage

be disconnected at the pump control until after initial

start-up. This will allow the pump to remain in its

"neutral" (zero-flow) position.

"Jog" or slowly rotate the vehicle engine until charge

pressure starts to rise. Start the vehicle engine and

run at the lowest possible RPM until charge pressure

has been established.

WARNING

Do not start vehicle engine unless pump is in

"neutral" position (0

° swashplate angle) and

the range control mechanism is in neutral.

Take precautions to prevent vehicle move-

ment in case pump is actuated during initial

start up.

Once charge pressure has been established, in-

crease speed to normal operating RPM. Charge

pressure should be 5.5 bar (80 psi) minimum and a

maximum of 9 bar (130 psi). If charge pressure is

incorrect, shut down and determine cause for im-

proper pressure.

Shut down vehicle engine and connect external con-

trol linkage to the pump. Start vehicle engine, check-

ing to be certain pump remains in neutral. Engage the

mechanical gearbox and, with vehicle engine at nor-

mal operating speed, slowly check for forward and

reverse vehicle operation.

Charge pressure should remain at 5.5 bar (80 psi)

minimum during forward or reverse operation. Con-

tinue to cycle slowly between forward and reverse for

at least five (5) minutes.

Shut down vehicle engine, remove gauges, and plug

ports. Check fluid level and add fluid if necessary.

Avoid overfilling unit. Overfilling unit will result in

additional horsepower loss and heat generation.

The transaxle is now ready for operation.

Acceptable fluids must have additives that provide

acceptable performance when operating with multi-

disk brake and clutch components.

Most premium tractor fluids are suitable for operation

in the IHT-M15. Mobil 424 or its equivalent is recom-

mended by the factory.

Automatic transmission fluids such as Type F and

5. Start-up, Fluids, and Filter

5.1 Fluids Specification

Dextron should not be used. Use of these fluids will

result in a reduction of component life.

Rapeseed-based oils are not recommended for use.

Premium synthetic ester oils, such as Mobil Syndraulic

46 should provide service life similar to mineral based

oils under similar conditions. Change interval must

be decreased to 75% of recommendations in section

5.2.

5.2 Start-up Procedure

IHT-M15 Start-Up, Fluids, and Filter 5

To ensure optimum service life of the IHT-M15

transaxle, regular maintenance of the fluid and filter

must be performed.

Check the housing daily for proper fluid level. The

fluid level should fall between the "Add" and "Full"

lines on the dipstick. Also check for the presence of

water (noted by a cloudy to milky appearance of the

fluid), and rancid fluid odor (indicating excessive

heat).

It is recommended that the fluid and filter be changed

per the vehicle/machine manufacturerÕs recommenda-

tions or initially after 200 hours and then at 600 hour

intervals of vehicle operation.

CAUTION

Avoid overfilling or underfilling the unit. Over-

filling unit will result in additional horsepower

loss and heat generation. Underfilling the unit

will in serious damage.

It may be necessary to change the fluid more fre-

quently than the above interval if the fluid becomes

contaminated with foreign matter (dirt, water, grease,

etc.) or if the fluid has been subjected to temperature

levels greater than the maximum recommended.

Never reuse fluid.

After filling, run the unit and its implement circuit

briefly and recheck the fluid level.

NOTE: When on a level surface, the proper oil

level is to the base of the fill level plug on the back

of the IHT-M15.

The filter should be changed whenever the fluid is

changed. See section 7.11 for instructions on chang-

ing the filter.

The transaxle is supplied with a filter installed at the

factory. A factory supplied filter replacement is rec-

ommended. A suction filter with time waited average

ratings of β

= 5.5 and β

= 75 is required.

Oil Drain

Fill Level Plug

5.3 Fluid and Filter Change

Fill Tube

Dip Stick

Filter

Location of Fluid and Filter Components

P100135

P100136

IHT-M15 Inspections and Adjustments 6

6. Inspections and Adjustments

6.1 Charge Pressure Priority Valve Inspection

Incorrect charge pressure can lead to improper func-

tioning of many systems. A charge pressure that is

too low or too high may be the result of the charge

pressure priority valve sticking. This can be remedied

by removing and cleaning the valve per Sec. 7.8.

Check charge pressure as follows.

WARNING

The following procedure requires the vehicle

to be disabled (wheels raised off the ground,

etc.) in order to prevent injury to the technician

and bystanders.

1. Disable vehicle by raising wheels off of ground.

2. To measure charge pressure, install a 35 bar (or

500 psi) pressure gauge in the charge pressure

gauge port.

3. Operate the system with the pump in "neutral"

(zero angle) and in forward and reverse when

measuring charge pressure.

Charge pressure should be between 5.5 and 9 bar

(80 to 130 psi) at 1800 engine rpm and a fluid

temperature of 49°C (120°F ).

If charge pressure is too low or high, follow Sec. 7.8

to remove and clean the charge pressure priority

valve. Ensure the valve and spring are reinstalled

properly.

Charge Pressure

Gauge Port

Charge Pressure Gauge Port

Location of Charge Pressure Priority Valve

E100033

P100155

Charge Pressure

Priority Valve

IHT-M15 Inspections and Adjustments 6

Implement circuit pressure can be measured, and the

implement relief valve can be adjusted. However, the

relief valve is set at the factory, and should not be

tampered with except to remedy an inadvertent ad-

justment.

WARNING

The following procedures require the vehicle

to be disabled (wheels raised off the ground,

etc.) in order to prevent injury to the technician

and bystanders.

Measuring Implement Circuit Pressure

1. With engine off, set a pressure gauge to measure

implement circuit pressure by teeing into the

implement hose that is connected to the imple-

ment circuit outlet port.

2. Measure standard implement pressure with en-

gine input speed at 1800 rev/min and the pump in

neutral.

The correct setting for implement circuit pressure will

vary depending on your application and gear ratios.

The "nominal" relief setting is set for 2 l/min (0.5 gpm)

flow moving through the valve. However, in checking

circuit pressure, it is easiest to measure pressure at

"full" relief flow (11 l/min (3 gpm)); this pressure will

measure 8 bar (120 psi) above the nominal setting.

As an example, for a nominal relief setting of "70 bar"

("1000 psi"), implement circuit pressure should read

78 ± 1 bar (1120 ± 15 psi) at full relief flow.

To adjust implement circuit pressure continue below.

(continued)

6.2 Implement Relief Valve Adjustment

Exploded View of Implement Relief Valve

on IHT-M15

Location of Implement Relief Valve

and Implement Circuit Port

78 bar

(1120 psi)

70 bar

(1000 psi)

2 l/min

(0.5 gpm)

11 l/min

(3 gpm)

"nominal" setting

"full" setting

graph to show trend only -- not exact

Trend Graph Showing Relation of ÒNominalÓ and

ÒFullÓ Implement Relief Valve Settings

E100034

P100157

G100001

Implement

Relief Valve

Implement Circuit

Outlet Port

IHT-M15 Inspections and Adjustments 6

Spring

Poppet

Adjusting Screw

O-Ring

Plug

Seal Lock Nut

Implement Relief Valve Components

(Do Not Remove When Engine Is On!)

Adjusting Implement Relief Valve Setting

WARNING

The implement relief circuit is under high pres-

sure. Do not remove the implement relief seal

lock nut and/or the adjusting screw.

1. Loosen the seal lock nut with an 7/8 in hex

wrench. Do not remove.

2. The adjustable screw (4 mm int. hex) sets the

pressure setting. Do not remove. With the pump

in neutral, adjust the screw and retighten the seal

lock nut. Observe the implement circuit pressure

gauge. Only a slight adjustment should be neces-

sary.

WARNING

The implement relief valve should only be set

at the setting specified for the model. Too high

of a setting can damage the unit or auxiliary

equipment, and harm the operator or bystand-

ers. Too low of a setting could weaken the

implement function.

3. After the proper setting is made, stop the engine.

Retorque the seal lock nut [33 Nm (24 ft

•

lbf)].

Remove the pressure gauge. The implement

circuit hose should be torqued to [41 Nm (30

•

lbf)].

E100035

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