924G and 924Gz Wheel Loaders Power Train Caterpillar

Show/hide table

Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the power train.

Show/hide table

Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

Electrical connections between harnesses may not be tight. Loose electrical connections cause continuous electrical problems or intermittent problems. Make sure that all connectors in the circuit are fastened correctly before tests are performed.

This test will determine if the electrical coil energizes. This test will determine if the plunger shifts in order to permit oil flow.

The sound of a click from the solenoid does not ensure that the plunger shifts. Checking an energized coil for magnetism with a screwdriver does not ensure that the solenoid plunger shifts. The following test will tell if the solenoid plunger is shifting.

Illustration 1	g00635048
(1) Forward high solenoid (2) Reverse solenoid (3) Forward low solenoid (4) First speed solenoid (5) Second speed solenoid (6) Third speed solenoid

1. Install a 1U-5481 Pressure Gauge Group and a 6V-3014 Hose Assembly with two 6V-4143 Couplers on the P2 pressure tap.

2. Engage the parking brake and start the engine. Run the engine at low idle.

3. Move the transmission neutralizer lockout switch to the ON position.
   Show/hide table

   Table 2

   Machine Speed and Direction	Solenoids that are Energized	Clutches that are Engaged
   First speed forward	(3) Forward low solenoid and (4) First speed solenoid	Forward low clutch and first speed clutch
   Second speed forward	(3) Forward low solenoid and (5) Second speed solenoid	Forward low clutch and second speed clutch
   Third speed forward	(3) Forward low solenoid and (6) Third speed solenoid	Forward low clutch and third speed clutch
   Fourth speed forward	(1) Forward high solenoid and (6) Third speed solenoid	Forward high clutch and Third speed clutch
   Neutral	None	None
   First speed reverse	(2) Reverse solenoid and (4) First speed solenoid	Reverse clutch and First speed clutch
   Second speed reverse	(2) Reverse solenoid and (5) Second speed solenoid	(Reverse clutch and Second speed clutch)
   Third speed reverse	(2) Reverse solenoid and (6) Third speed solenoid	Reverse clutch and Third speed clutch

4. Depress the brake pedal and hold the brake pedal. While you watch the pressure gauge, move the shift lever from the NEUTRAL position to the FORWARD position. The needle on the pressure gauge should drop and the needle on the pressure gauge should then return to the original pressure. Shift through all FORWARD speeds. The same pressure drop should be noted in all speeds.

5. Perform the above step for all REVERSE speeds. The pressure drop should be noted in all REVERSE speeds.

If the pressure drop can be seen, the solenoid and the related electrical circuit is functioning.

If you can not see the pressure drop, use a screwdriver in order to check for an energized solenoid coil. If the screwdriver indicates that the coil is energized, the problem is in the solenoid cartridge. The problem could be a bent stem. The problem could be a dirty screen or a clogged screen. The problem could be a weak spring or a broken spring.

If the screwdriver does not indicate that the coil is energized, the problem is in the electrical circuit. Possible problems include the following items:

• The solenoid coil is bad.

• The connection in the connector is bad.

• Broken wire

• The shift control is faulty.