Testeo Lock Up

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Torque Converter Lockup Clutch Maximum Pressure - Test

SMCS - 3115-081-PX ; 5073-081-PX

Note: Make sure that the filters and the screens are clean before you test any pressures. Make sure that the oil is at operating temperature before youperform this test.

This test will show the following conditions if the conditions exist:

l The maximum lockup pressure is correct.

l The operation of the modulation reduction valve is correct.

Procedure

1. Disconnect the electrical harness from the lockup clutch solenoid. Disconnect the upshift solenoid and the downshift solenoid.

2. The transmission control must be in NEUTRAL and the transmission rotary selector spool must be in NEUTRAL-1.

3. The downshift solenoid remains activated while the transmission is in NEUTRAL. This causes +24 volts to be supplied to the electrical harness

for the downshift solenoid.

4. Use two Sure-Seal 2-pin connectors and two 16 gauge wires in order to make a jumper harness. The two wires should be approximately 4.5 m (15ft) long. Connect one end of the jumper harness to the harness for the downshift solenoid.

Cerrar SIS

Pantalla anterior

Producto: TRUCKModelo: 777D TRUCK AGCConfiguracin: 777D Off-Highway Truck AGC00001-UP (MACHINE)POWERED BY 3508B Engine

N m e r o d e m e d i o - R EN R 3 32 0 - 0 7 F ec h a d e p u b l i c ac i n - 0 1 / 0 8 / 2 0 0 7 F ec h a d e a c t u a l iz a c i n - 0 9 / 0 8 / 2 0 0 7

i01908516

Table 1

Required Tools

Part Number Description Quantity

198-4240 Digital Pressure Indicator 1

Personal injury or death can result from sudden machine movement.

Sudden movement of the machine or release of air pressure or oilpressure can cause injury to persons on or near the machine.

To help prevent possible injury before testing and adjusting any airsystem or hydraulic system, perform the procedure in the Testing andAdjusting, "General Information" section.

Illustration 1 g00650229

Pgina 1 de 3777D Off-Highway Truck AGC00001-UP (MACHINE) POWERED BY 3508B Engine(SEBP3016 - 79) - Estructura del producto

28-08-2007https://sis.cat.com/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/sisweb/productsearch/productheaderinfoframeset.js...


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5. Connect 198-4240 Digital Pressure Indicator to the nipple at pressure tap (DD) .

6. Start the engine while the parking brake is activated. Run the engine at the low idle rpm with the transmission in NEUTRAL-1. The pressure onthe gauge must be 0 kPa (0 psi).

Note: In order to maintain 1300 rpm for this test, disconnect the throttle position switch. Then use the throttle backup switch.

7. Look at the pressure gauge. Connect the jumper harness from the downshift solenoid to the lockup clutch solenoid. Run the engine at mediumidle. Medium idle is approximately 1300 rpm. The pressure on the gauge must be 2140 70 kPa (310 10 psi).

8. Disconnect the jumper harness from the lockup clutch solenoid. The pressure on the gauge must be 0 kPa (0 psi).

9. Stop the engine. After the pressure is correctly set, remove the test equipment.

Problem: The oil pressure is not 0 kPa (0 psi) when the lockup clutch solenoid is deactivated.

Probable Cause

l Selector piston (1) is stuck.

l Spring (8) is weak or broken.

(DD) Pressure tap for the lockup clutch pressure "LU"

Illustration 2 g00525482

Synchronizing valve

(1) Selector piston

(2) Load piston

(3) Load piston plug

(4) Inner spring

(5) Outer spring

(6) Load piston orifice

(7) Shuttle valve

(8) Spring




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l Shuttle valve (7) is stuck.

l The lockup clutch solenoid is bad. Perform the Testing and Adjusting, "Solenoid Valve - Test".

Problem: The oil pressure is 0 kPa (0 psi) with the lockup clutch solenoid activated.

Probable Cause

l There is either a small amount of pilot oil or no pilot oil. Perform the test in the Testing and Adjusting, "Torque Converter Lockup Clutch PilotPressure - Test and Adjust".

l Incorrect operation of shuttle valve (7)

l Outer spring (5) is weak or broken and/or inner spring (4) is weak or broken.

Problem: The oil pressure is too low with the lockup clutch solenoid activated.

Probable Cause

l Load piston plug (3) is not installed.

l Load piston orifice (6) is plugged.

l Load piston (2) is stuck, and/or selector piston (1) is stuck.

l Outer spring (5) is weak or broken, and/or inner spring (4) is weak or broken.

l Incorrect outer spring (5) and/or inner spring (4) .

l The primary pressure setting is incorrect. Perform the test in the Testing and Adjusting, "Torque Converter Lockup Clutch Primary Pressure -Test and Adjust".

Problem: The oil pressure slowly decreases or the low pressure remains with the lockup clutch solenoid deactivated.

Probable Cause

l Incorrect operation of shuttle valve (7)

l Load piston (2) is stuck and/or selector piston (1) is stuck.

Problem: The oil pressure is too high with the lockup clutch solenoid activated.

Probable Cause

l The primary pressure setting is incorrect. Perform the test in the Testing and Adjusting, "Torque Converter Lockup Clutch Primary Pressure -Test and Adjust".

Copyright 1993 - 2007 Caterpillar Inc.Todos los derechos reservados.Red privada para licenciados del SIS.

Tue Aug 28 10:02:06 UTC-0400 2007



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