554 and 574 Forwarders Power Train Gearshift Pressures - Test

The following procedure is used in order to verify that the correct oil pressure to the transmission gearbox is within specification. The specifications are listed in Table 1 and Table 2.

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Table 1
Pressures to Shift the Transmission Gearbox
Shift Pressure	Speed Selection
-	Low Speed	High Speed
Minimum Pressure	1500 kPa (215 psi)	1500 kPa (215 psi)
Maximum Pressure	3500 kPa (500 psi)	3500 kPa (500 psi)

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Table 2
Pressure to Shift the Eight Wheel Drive Disengage
Minimum Pressure	Maximum Pressure
1500 kPa (215 psi)	3500 kPa (500 psi)

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Table 3
Required Tools
Qty.	Part No.	Description
2	8T-0856	Pressure Gauge (0 to 6,000 kPa (0 to 870 psi))

The gearshift valve is located on the inside of the left frame rail under the cab.

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Illustration 1	g00916293
(1) Eight wheel drive disengage pressure tap. (1a) Gearshift pressure tap.

Connect a 8T-0856 Pressure Gauge (0 to 6,000 kPa (0 to 870 psi)) to each pressure tap (1) .
Note: Two pressure taps are installed on the gearshift valve. One pressure tap, (1a) reads the gearshift pressure. One pressure tap, (1) reads the eight wheel drive disengage pressure.

Gearshift Valve Pressure Test and Adjust

Testing the Gearshift Valve Pressure

Start the machine.

Warm the oil in the transmission gearbox and the hydraulic tank to the normal operating temperature.

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Illustration 2	g00932267
Mode Selector Switch

Place the machine in the ROADING MODE.

If a new solenoid valve was installed, shift the transmission at least 12 times into a gear that uses the solenoid valve.

Place the direction selector switch in the NEUTRAL position.

Place the parking brake switch in the ON position.

Run the engine speed at low idle.

Move the speed selector switch to the speed that is being tested. This will cause the gearshift valve to shift the gearshift cylinder that is located on the side of the transmission gearbox.
Note: Do not depress the accelerator pedal.

Read the pressure on the 8T-0856 Pressure Gauge (0 to 6,000 kPa (0 to 870 psi)) for the transmission gearbox speed that is being tested.
The specified pressure for gear engagement is listed in Table 1.

Move the direction selector switch to the NEUTRAL position and turn off the engine.

If the gearshift pressures are within specification, disconnect the test equipment. Adjustment is not necessary. If the gearshift pressures are not within specification, proceed to the section that is entitled "Adjusting the Gearshift Pressure".

Adjusting the Gearshift Pressure

If the gearshift pressure is not within specifications, use the following procedure in order to adjust the gearshift valve.

Start the machine.

Ensure that the hydraulic oil is at the normal operating temperature.

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Illustration 3	g00932267
Mode Selector Switch

Place the machine in the ROADING MODE.

Place the direction selector switch in the NEUTRAL position.

Place the parking brake switch in the ON position.

Run the engine speed at low idle.

Move the speed selector switch to the speed that is being tested. This will shift the gearshift cylinder that is located on the side of the transmission gearbox.
Note: Do not depress the accelerator pedal.

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Illustration 4	g00916661
Gearshift Valve Valve Removed from Machine for Clarity

Loosen locknut (4) .

Read the pressure on the 8T-0856 Pressure Gauge (0 to 6,000 kPa (0 to 870 psi)) while the following adjustment is being performed.
The specified pressure for gear engagement is listed in Table 1.

If the pressure is higher than specification, turn adjustment screw (5) counterclockwise in order to lower the pressure.

If the pressure is lower than specification, turn adjustment screw (5) clockwise in order to raise the pressure.

Tighten locknut (4). Ensure that the pressure reading on the gauge is correct.

Move the direction selector switch to the NEUTRAL position and turn off the engine.

Disconnect the test equipment.

Eight Wheel Drive Disengage Pressure Test and Adjust

Testing the Eight Wheel Drive Disengage Pressure

If the eight wheel drive disconnect pressure is not within specifications, follow the procedure below in order to adjust the eight wheel drive disconnect valve.

Start the machine.

Warm the oil in the transmission gearbox and the hydraulic tank to the normal operating temperature.

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Illustration 5	g00932267
Mode Selector Switch

Place the machine in the ROADING MODE.

Ensure that the direction selector switch is in the NEUTRAL position.

Place the parking brake switch in the ON position.

Run the engine speed at low idle.

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Illustration 6	g00916614
Location of the Eight Wheel Drive Disengage Cylinder

Move the eight wheel drive disengage switch to the ON position. This will cause the eight wheel drive disengage valve to shift the eight wheel drive disengage cylinder that is located inside the rear of the transmission gearbox.
Note: Do not depress the accelerator pedal.

Loosen purge plug (6) slightly in order to purge any air in the system prior to checking the pressure.

Read the pressure on the 8T-0856 Pressure Gauge (0 to 6,000 kPa (0 to 870 psi)) for the eight wheel drive disengage.
The specified pressure for the eight wheel drive disengage is listed in Table 2.

Turn off the engine.

If the eight wheel drive disengage pressure is within specification, disconnect the test equipment. Adjustment is not necessary. If the eight wheel drive disengage pressure is not within specification, proceed to the section that is entitled "Adjusting the Eight Wheel Drive Disengage Pressure".

Adjusting the Eight Wheel Drive Disengage Pressure

If the eight wheel drive disengage pressure is not within specifications, use the following procedure in order to adjust the eight wheel drive disengage valve.

Start the machine.

Ensure that the hydraulic oil is at the normal operating temperature.

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Illustration 7	g00932267
Mode Selector Switch

Place the machine in the ROADING MODE.

Place the direction selector switch in the NEUTRAL position.

Place the parking brake switch in the ON position.

Run the engine speed at low idle.

Turn the eight wheel drive disengage switch to the ON position. This will shift the eight wheel drive disengage cylinder that is located on the rear of the transmission gearbox.
Note: Do not depress the accelerator pedal.

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Illustration 8	g00916650
Eight Wheel Drive Disengage Valve Valve Removed from Machine for Clarity

Loosen locknut (2) .

Read the pressure on the 8T-0856 Pressure Gauge (0 to 6,000 kPa (0 to 870 psi)) while the following adjustment is being performed.
The specified pressure for the eight wheel drive disengage is listed in Table 2.