980K Wheel Loader Caterpillar

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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.

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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.

Problem List

Note: Many of the following problems can create diagnostic codes or event codes in ET. These codes can help find the root cause of the problem. ET should be used to retrieve the logged codes and active codes.

1. Low stall speed.

2. High stall speed in both directions.

3. High stall speed in one gear or in one direction.

4. There is high converter pressure.

5. There is low converter pressure.

6. The torque converter gets hot.

7. The torque converter lockup clutch does not engage.

Probable Causes

Problem 1

Low stall speed.

Probable Causes

1. Engine performance is not correct.

2. The oil is cold.

Problem 2

High stall speed in both directions.

Probable Causes

1. The oil level is low.

2. There is air in the oil.

3. Clutches are slipping.

4. There is torque converter failure.

Problem 3

High stall speed in one gear or in one direction.

Probable Causes

1. There is a leak in the clutch circuit.

2. There is a clutch failure in the gear that has a high stall speed or in the direction that has a high stall speed.

Problem 4

There is high converter pressure.

Probable Causes

1. There is a restriction inside the converter.

2. The oil passage is restricted or the oil cooler is restricted.

Problem 5

There is low converter pressure.

Probable Causes

1. The torque converter inlet relief valve is stuck.

2. There is low pump flow or pressure.

Problem 6

The torque converter gets too hot.

Probable Causes

1. There is too much load which causes the torque converter to slip.

2. The transmission gear is incorrect for the load on the machine. Shift to a lower gear.

3. The oil level is incorrect in the transmission.

4. The water level is low in the engine radiator.

5. There are restrictions in the oil cooler or lines.

6. There is not enough oil to the torque converter because the torque converter inlet relief valve is bypassing too much flow.

7. There is not enough oil to the converter because of low pump flow or pressure.

Problem 7

The torque converter lockup clutch does not engage.

Probable Causes

1. The switch for the lockup clutch is not in the ON position.

2. The switch for the lockup clutch is faulty.

3. The transmission output speed sensor is faulty.

4. The modulating valve for the torque converter lockup clutch is faulty.

5. There is a problem in the electrical circuit.