D8T Track-Type Tractor Caterpillar

Transmission Clutch Pressure - Test

Usage:

D8T AW4

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Hydraulic oil pressure can remain in the hydraulic system on this machine after the engine and pump have been stopped. Serious injury can result if this pressure is not released before any service is done on the hydraulic systems. In order to prevent possible injury, release the hydraulic system pressure before working on any fitting, hose, or hydraulic component.
Lower all attachments to the ground before service is started. If the hydraulic system must be serviced, tested, or adjusted with the attachment in the raised position, the attachments and lift cylinders must be supported properly.

Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made.

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NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Dispose of all fluids according to local regulations and mandates.

Specifications

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Table 1
Low Idle Clutch Pressure
Date	Equipment ID Code
	Recommended
Clutches 1, 2, 4, and 5	2580 ± 105 kPa (374 ± 15 psi)
Clutches 3 and 6	2420 ± 105 kPa (351 ± 15 psi)

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Table 2
Transmission Gear	Clutches Engaged	Operator Speed Setting
4F	2, 4, 5	2.3F — 3.0F
3F	2, 4, 6	1.6F — 2.2F
2F	2, 3, 4	1.1F — 1.5F
1F	2, 3, 6	0.1F — 1.0F
1R	1, 3, 5	0.6R — 1.5R
2R	1, 3, 6	1.6R — 2.0R
3R	1, 3, 4	2.1R — 2.5R
4R	1, 4, 6	2.6R — 3.0R

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Table 3
Checklist for Transmission Clutch Speed Settings
Transmission Gear	Operator Speed Setting	Transmission Clutch	Pressure Measurement	Transmission Clutch	Pressure Measurement	Transmission Clutch	Pressure Measurement
4F	3.0F	No. 2 Clutch		No. 4 Clutch		No. 5 Clutch
3F	2.0F	No. 2 Clutch		No. 4 Clutch		No. 6 Clutch
2F	1.5F	No. 2 Clutch		No. 3 Clutch		No. 4 Clutch
1F	1.0F	No. 2 Clutch		No. 3 Clutch		No. 6 Clutch
1R	1.5R	No. 1 Clutch		No. 3 Clutch		No. 5 Clutch
2R	2.0R	No. 1 Clutch		No. 3 Clutch		No. 6 Clutch
3R	2.5R	No. 1 Clutch		No. 3 Clutch		No. 4 Clutch
4R	3.0R	No. 1 Clutch		No. 4 Clutch		No. 6 Clutch

Reference

Reference: Operation and Maintenance Manual, SEBU9417, System Pressure Release

Introduction

The following transmission clutch pressures can be tested in two ways.

While in selected gear. Refer to Table 2 for clutch engagement list based on gear selection.
Performing a "Transmission Hydraulic Control Clutch Pressure Test" in Electronic Technician (ET) and selecting the clutches individually.

Required Tools

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Illustration 1	g06283838
Tooling (T1)

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Illustration 2	g06283840

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Table 4
Required Tools
Tooling	Item	QTY	Part Number	Description
T1		1	198-4240	Digital Pressure Indicator Group
	T1a	1	198-4234	Digital Pressure Indicator
	T1b	1	198-4237	Pressure Sensor (0 psi to 500 psi)
	T1c	1	198-4236	Adapter Cable Assembly
T2		1	466-6258⁽¹⁾	Communication Adapter Gp
	T2a	1	370-4617	Cable As (USB PC Communication)
	T2b	1	317-7485	Communication Adapter III
	T2c	1	457-6114	Cable As (Data Link)

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⁽¹⁾	Cat Electronic Technician (ET) and Software CD, NETG5057 are required when using the communication adapter.

Test Preparation

Move the machine to a smooth horizontal location.
Lower all the implements.
Shut off the engine.

Turn the key to the ON position. Make sure that the implement lockout switch is turned to the UNLOCKED position.

Reference: Refer to the Operation and Maintenance Manual, SEBU9417, System Pressure Release for correct procedure to release any pressure.

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Illustration 3	g06037960
The pressure taps for the transmission clutches are on the back of the transmission housing. (1) Modulating valve for No. 1 clutch (2) Modulating valve for No. 2 clutch (3) Modulating valve for No. 3 clutch (4) Modulating valve for No. 4 clutch (5) Modulating valve for No. 5 clutch (6) Modulating valve for No. 6 clutch (7) Transmission output speed sensors (8) Main relief valve

Remove cover to gain access to the pressure taps.
Attach one set of tooling (T1) to each pressure tap. Label each set of tooling (T1) as the tooling is attached to a valve.

Test Procedure - In Gear

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Illustration 4	g06302081
(9) Autoshift disable switch (10) Speed range selector

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Illustration 5	g06302082
(9) Autoshift disable switch

Disable autoshift mode (9).
Start the engine. Warm the power train oil to a temperature of 80° ± 5°C (176° ± 9°F).
Disengage the parking brake. Engage the service brakes.
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Illustration 6 g06046898

(10) Speed range selector
Operate the engine at LOW IDLE.
Manipulate the speed range selector (10) to produce each speed setting shown in Table 2.
Check the pressure at tooling (T1) for each clutch. The pressure for clutches 1, 2, 4, and 5 should be 2580 ± 105 kPa (374 ± 15 psi) and clutches 3 and 6 should be 2420 ± 105 kPa (351 ± 15 psi).
Use Table 2 to check all the other combination of clutches. Copy Table 3 and record the pressure measurements in the table 1.

Test Procedure - ET

Connect the tooling (T2) to the diagnostic port on the tractor.
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Illustration 7 g06306872
Connect to ET.
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Illustration 8 g06306875
Select "Diagnostics", then "Diagnostic Tests" from the drop-down menu.
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Illustration 9 g06306877
Select "Transmission Hydraulic Control Clutch Pressure Test".
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Illustration 10 g06306882
Read the warning and select "Accept".
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Illustration 11 g06306888
Follow the onscreen instructions in Cat® ET. Once all conditions are met, select "Next" on the bottom of the Cat® ET screen.
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Illustration 12 g06306897
"Transmission Pressure Test Selected Clutch" will show the clutch being calibrated.
The arrows at the bottom of the screen are used to select each clutch.
Select "Activate" to check the clutch pressure for each clutch.
Note: All clutch pressure checks will be performed at Low idle and the "Raise Engine Speed" button is not available on the machine.
All clutch pressures will be commanded to maximum pressure of 2758 kPa (400 psi), Record all pressure measurements in Table 5.
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Table 5
Transmission Gear Pressure Measurement

LUC

Clutch 1

Clutch 2

Clutch 3

Clutch 4

Clutch 5

Clutch 6

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Illustration 13 g06306900
Click the "Next" button when testing all clutches is complete.