GEAR-INTERNAL 3167898 - Caterpillar

Brake Does Not Release
Before you complete any procedure, read Troubleshooting, "Machine Preparation for Troubleshooting" and Troubleshooting, "Visual Inspection" in this module.Probable Cause
Neutral default strategy
Contamination of the hydraulic system oil
Insufficient pressure oil to the brakes
Transmission drag
Insufficient system pressure
Failed brake components
Brake control valve
Proportional solenoid valveRecommended Actions
Follow this procedure if the machine does not move or if the machine moves slowly.Neutral Default Strategy
Neutral Default Strategy is programmed in the software for the transmission in order to engage the service brakes on the machine under certain conditions. Neutral Default Strategy will automatically apply the service brakes for 10 seconds for the power train to stabilize during the start-up of the machine.ReferenceFor more information about Neutral Default Strategy, refer to (D8T) Specifications, Systems Operation/Testing, and Adjusting, UENR1389, "Transmission".ReferenceFor more information about Neutral Default Strategy, refer to (D9T) Specifications, Systems Operation/Testing, and Adjusting, KENR8943, "Transmission".Contamination Of The Hydraulic System Oil
Determine that the symptom is active.If the symptom is intermittent, then a probable cause is oil contamination.
Complete this procedure only if the symptom is active.Results
ACTIVE: Proceed to "Insufficient Pressure Oil To The Brakes".
NOT ACTIVE: If the symptom is not active, oil contamination may be the problem. Change the power train oil. Change the oil filter element and clean the screens.
Stop.Insufficient Pressure Oil To The Brakes
Check the brake pressure.The brakes are engaged by spring force. The brakes are released by pressure oil which is sent from the steering clutch and brake control valve to the brakes. Therefore, insufficient pressure oil to the brakes is a probable cause of the symptom.
ReferenceRefer to (D8T) Specifications, Systems Operation/Testing, and Adjusting, UENR1389, "Steering Clutch and Brake Pressure - Test".ReferenceRefer to (D9T) Specifications, Systems Operation/Testing, and Adjusting, KENR8943, "Steering Clutch and Brake Pressure - Test".Expected Results
The pressure is correct.Results
OKAY: The pressure is correct. Proceed to "Transmission Drag".
NOT OKAY: The pressure is not correct. Proceed to "Insufficient System Pressure".Transmission Drag
ReferenceRefer to (D8T) Specifications, Systems Operation/Testing, and Adjusting, UENR1389, "Transmission Clutch Pressure - Test".ReferenceRefer to (D9T) Specifications, Systems Operation/Testing, and Adjusting, KENR8943, "Transmission Clutch Pressure - Test".
Place pressure gauges on all transmission clutches.
Operate the engine.
Disengage the parking brake.
Press down the service brake pedal in order to engage the brakes.
Shift through all the transmission gears.
Check that the proper clutches engage for each gear.
Check that the clutches disengage properly for each gear. The clutch that is disengaged should have a pressure below 137 kPa (20 psi).Expected Results
The transmission clutches engage and the transmission clutches disengage properly.Results
OKAY: The engagement of the transmission clutches was eliminated as the source of the symptom. Since the brake pressure was correct, then the brake control valve was eliminated as the cause of the symptom. Therefore, the brake is the probable cause of the symptom. Proceed to "Failed Brake Components".
NOT OKAY: The transmission clutches do not engage properly.Proceed to "The Transmission Clutch Does Not Engage" in Troubleshooting, "Transmission Clutch" in this module.
NOT OKAY: The Transmission Clutch Is Engaged and the Clutch Does Not Release.Proceed to "The Transmission Clutch Is Engaged and the Clutch Does Not Release" in Troubleshooting, "Transmission Clutch" in