Event Codes for In Gear, Transmission Slip Detection
The following table defines the codes related to a Transmission Slip event.
| Event Code (Warning Level) | Code Description |
|---|---|
| E2201 (2) | Transmission Slip Detected In FIRST Forward Gear. |
| E2202 (2) | Transmission Slip Detected In SECOND Forward Gear. |
| E2203 (2) | Transmission Slip Detected In THIRD Forward Gear. |
| E2204 (2) | Transmission Slip Detected In FOURTH Forward Gear. |
| E2205 (2) | Transmission Slip Detected In FIFTH Forward Gear. |
| E2301 (2) | Transmission Slip Detected In FIRST Reverse Gear. |
| E2302 (2) | Transmission Slip Detected In SECOND Reverse Gear. |
| E2303 (2) | Transmission Slip Detected In THIRD Reverse Gear. |
Transmission slip occurs when the load on the machine exceeds the capacity of the clutch to transmit torque (torque capacity). Torque capacity depends on both the pressure at the clutch and the friction at the clutch. A deficiency in either will allow the clutch to slip when the load exceeds the torque capacity. Problems with the electrical or hydraulic systems that control the clutch can result in a pressure deficiency. Problems with the friction material, the clutch plates, or even the wrong oil type, may result in a friction deficiency.
While the transmission is in gear, the Gear Slip Detect Feature continuously monitors the torque converter and transmission output speeds, to determine whether the transmission is slipping. When slippage in a particular gear is detected, the Transmission ECM limits the engine torque and increases the transmission system pressure to prevent additional slip and protect the transmission. The Transmission ECM automatically maintains the increased system pressure for the gear in which slip was detected. This increased system pressure is called Transmission Main Relief Valve Compensation.
If limiting engine torque and increasing system pressure does not stop the transmission clutch slip, then the Transmission ECM will lock out the problem gear. The ECM also activates an event code to assist in troubleshooting the problem. See Table 1 for a list of applicable event codes related to the Slip Detect Feature. Restarting the machine clears the active event code and allows temporary operation. Only light-duty activities should be attempted. The lock-out will reoccur if a transmission gear slip is detected again.
Transmission speed sensor diagnostics and transmission slip events are interrelated. The "In Gear Slip Detect" feature detects clutch slip as long as the torque converter and the transmission output speed sensors are working properly. If there are problems with these sensors, then this feature can falsely detect slip. Follow this transmission slip trouble shooting procedure before the Speed Sensor Troubleshooting Procedure whenever transmission slip events and both transmission output speed sensor diagnostics are active at the same time.
If a hardware problem is identified and corrected through this troubleshooting procedure, the "Transmission Main Relief Valve Compensation" should be reset through Cat Electronic Technician (Cat® ET) after the repair is completed.
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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine. |
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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. |
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Escaping fluid under pressure, even a pinhole size leak, can penetrate body tissue, causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak. |
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Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates. |
Operate the machine in each direction and in all speeds. If any abnormal noises are present, find the sources of the noises.
Make sure that you check for any service codes that have been generated before troubleshooting a problem.
Reference: For more information on checking for service codes with the Information Display, refer to Systems Operation, UENR3110, "Service Menu".
Reference: For more information on checking for service codes with Cat® ET, refer to Troubleshooting, "Determining Diagnostic Trouble Codes".
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| Illustration 1 | g03722228 |
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Transmission Pressure Tap Panel (located on right-hand side on 950M and 962M) (1) Steering Load Signal Pressure Tap (2) Torque Converter Outlet Pressure Tap (3) Lock Up Clutch Pressure Tap (4) Torque Converter Inlet Pressure Tap (5) Transmission Oil Pressure (eMRV) (6) Transmission Pressure Tap for Clutch 1 "Forward - Low" (7) Transmission Pressure Tap for Clutch 2 "Forward - High" (8) Transmission Pressure Tap for Clutch 3 "Reverse" (9) Transmission Pressure Tap for Clutch 4 (10) Transmission Pressure Tap for Clutch 5 (11) Transmission Pressure Tap for Clutch 6 | |
Transmission Clutch Slips Troubleshooting Procedure
Note: For the following procedures, Cat® ET will be required to monitor the machine. Prior to beginning this procedure, update to the latest version of Cat® ET. Connect to the service port of the machine and open the Cat® ET program.
During parts of this troubleshooting procedure, the technician will be required to check pressures for specific components. Illustration 1 details the locations for each of the remote pressure taps on the 950M and 962M machines.
When the troubleshooting process is complete and all repairs have been made, clear all logged diagnostics.
| Troubleshooting Test Steps | Values | Results |
|---|---|---|
| 1. Check for Existing Conditions Diagnosed by the ECM. Purpose: This step determines whether the Electronic Control Module (ECM) has detected any fault conditions since the last power cycle. These conditions could be contributing factors to a transmission clutch slip event. A. Park the machine on a clean, level surface. Turn key start switch and disconnect switch to the ON position. B. Connect the machine to a laptop computer equipped with the latest version of Cat® ET. Establish ET connection. C. With the parking brake engaged and the transmission in the NEUTRAL position, start the machine. D. Review the list of active diagnostic and/or event codes listed in Cat ET. Record the information for later reference in this troubleshooting process. E. Run the engine until the transmission oil temperature exceeds F. With the transmission still in NEUTRAL, hold the service brake and simultaneously apply full throttle. Check for Torque Converter Output Speed (TCOS). G. Turn the key switch to the OFF position. |
A DTC Code 672 is active. This fault is related to a failure of the Torque Converter Output Speed Sensor. A DTC Code ranging from 1401 through 1406 is active. These codes relate to a failure of a specific transmission solenoid. A DTC Code 3737 is active. This fault is related to a failure of the transmission main relief valve. The TCOS should read non-zero. Event Code E329 is active. This event code indicates that the transmission filter is plugged. |
NOT OK: DTC 672 code related to the Torque Converter Output Speed Sensor is active.
Repair: Follow the procedure described in "Speed Sensor - Test" section of this manual to check and repair the speed sensor circuit. After completing the procedure, confirm that the speed sensors are functioning correctly. NOT OK: DTC codes ranging from 1401 through 1406, relating to the transmission solenoids, are active. Repair: Follow the procedure described in "Solenoid - Test" section of this manual to check and repair the transmission solenoids. NOT OK: DTC Code 3737, relating to the transmission main relief valve, is active. Repair: Follow the procedure described in "Solenoid - Test" section of this manual to check and repair the solenoid for the transmission main relief valve. NOT OK: The TCOS is reading zero speed. Repair: Follow the procedure described in "Speed Sensor - Test" section of this manual to check and repair the speed sensor circuit. After completing the procedure, confirm that the speed sensors are functioning correctly. NOT OK: Event Code E329 is logged in Cat ET. Repair: Replace the transmission filter, if required. After the filter is changed, check for other event or diagnostic codes related to the bypass circuit. Make further checks of the circuit if codes are logged. Use the appropriate troubleshooting procedure to correct the diagnostic or event codes. OK: No Codes are detected. Proceed to Test Step 2 only after all conditions have been corrected. |
| 2. Check The Transmission Pump Pressure using the Cat ET eMRV Service Test. Purpose: This step determines if the eMRV and transmission oil pump are functioning properly. Note: Before starting this procedure, confirm that the transmission oil is filled to the correct level. A. Park the machine on a clean, level surface. Turn the key switch and battery disconnect to the ON position. B. Connect the machine to a laptop computer equipped with the latest version of Cat® ET. Establish ET connection. C. With the parking brake engaged, and the transmission in the NEUTRAL position, start the machine. D. While in NEUTRAL, verify the transmission clutch solenoid modulating valve is functioning. Refer to Testing and Adjusting, UENR3110, "Transmission Pressures – Test and Adjust" for the proper procedure for checking the Transmission Clutch Solenoid Modulating Valve. E. While in NEUTRAL, verify the transmission neutral clutch pressure is within spec. Refer to Testing and Adjusting, UENR3110, "Transmission Pressures – Test and Adjust" for the proper procedure for checking the Transmission Clutch Pressure. F. After verifying that the neutral clutch pressure is within spec, Refer to Testing and Adjusting, UENR3110, "Transmission Pressures – Test and Adjust" for the proper procedure for checking the Transmission Pump Pressure. |
Refer to Table 1 in Testing and Adjusting, UENR3110, "Transmission Pressures - Test and Adjust" for a list of the required pressure specifications. Compare measured pressures to the limits given in the Cat ET "Transmission Main Relief Valve Service Test". |
Not OK: No rise in neutral clutch pressure.
Repair: Check Cat ET for active diagnostic codes. Perform continuity checks of wiring harness and inspect for damage. Repair any problems associated with the circuit. Repeat the test after repairs are completed. NOT OK: The required pressure difference between the transmission pump and the neutral clutch is out of range. Repair: Temporarily replace the neutral clutch valve and repeat the pressure test. If the problem persists after replacing the valve, the transmission clutch may have an internal leak. Neutral clutch pressures that are not within spec can affect the results of the "Transmission Main Relief Valve Service Test". Reset the "Transmission Main Relief Valve Service Test" through Cat ET after permanently replacing any components. OK: The measured pressure difference between the transmission pump and the neutral clutch is within spec. NOT OK: The measured pump pressures are NOT within spec during the "Transmission Main Relief Valve Service Test". Repair: Temporarily replace the eMRV and repeat the "Transmission Main Relief Valve Service Test". If the pump pressures are still NOT within spec after replacing the eMRV, the transmission pump may have a problem. Reset the "Transmission Main Relief Valve Compensation" through Cat ET after permanently replacing any components. OK: The measured pressures are all within spec. Proceed to Test Step 3. |
| 3. Check The Transmission Clutch Pressures. Purpose: This step determines if the transmission clutch pressures are within spec. Note: Before starting this procedure, check the transmission oil level and adjust to the correct level as needed. Note: Refer to Illustration 1 for the location of individual pressure tap locations for checking clutch pressure. A. Check the Transmission Clutch Solenoid Modulation Valve. Refer to ITesting and Adjusting, UENR3110, "Transmission Pressures - Test and Adjust" for the proper procedures for checking the Transmission Clutch Solenoid Modulating Valve. B. Check the Transmission Clutch Pressures. Refer to Testing and Adjusting, UENR3110, "Transmission Pressures – Test and Adjust" for the proper procedure for checking the Transmission Clutch Pressure. |
Refer to Testing and Adjusting, UENR3110, "Transmission Pressures - Test and Adjust" for a list of the required pressure specifications and tools. |
NOT OK: No rise in clutch pressure is seen when shifting the transmission into gear. Repair: Check Cat ET for active diagnostic codes. Perform continuity checks of wiring harness and inspect for damage. Repair any problems associated with the circuit. Repeat the test after repairs are completed. NOT OK: The required pressure difference between the transmission pump and a clutch is out of range. Repair: For each clutch that did not meet specifications or the measured pressure is unstable, temporarily replace the valve on that clutch and repeat the pressure test. If the problem persists after replacing the valve, the transmission clutch may have an internal leak. Reset the"Transmission Main Relief Valve Compensation" through Cat ET after permanently replacing any components. OK: All measured pressures are within specifications. Proceed to Test Step 4. |
| 4. Check The Transmission Clutches For Actual Slip with a Stall Test. Purpose: This step checks the clutch friction material. A. While monitoring the machine with Cat ET, start and run the machine until the transmission fluid exceeds B. In Cat ET, set the "Integrated Braking System Manual Mode Enable Status" to disabled. C. Set the transmission to "MANUAL" mode. D. Disable the neutralizer function using the keypad to the right of the operator. E. Apply the service brakes, run the engine at low idle, and shift the transmission into First Speed Forward. Allow time for the shift to complete. F. CAUTION: This step can create machine motion. Ensure that the surrounding area is clear before proceeding. If the transmission overheats, wait until the transmission cools, before proceeding. While in gear, gradually throttle up the engine. If a slip event is logged in Cat ET, note the shift position. Once the engine reaches high idle or the machine begins to move, throttle back the engine to low idle. G. Repeat part F for all shift positions. |
Event Codes E2201-E2205 and/or E2301-E2303. | NOT OK: Transmission slip was detected. Event Codes E2201-E2205, E2301-E2303.
Repair: The clutch friction material may have a problem. Begin investigation for friction material damage. · Check transmission filter and screens. · Check transmission oil sample. If evidence of a friction material is found, determine root cause for clutch material failure. Contact DSN for assistance. Reset the"Transmission Main Relief Valve Compensation" through Cat ET after permanently replacing any components. OK: NO transmission slip was detected. Proceed to Test Step 5. |
| 5. Check The Transmission Output Speed Sensor. Purpose: This step determines whether the Transmission Output Speed (TOS) Sensor is working correctly. A. Drive the machine around and check that the TOS sensor is reading non-zero. B. Use the Troubleshooting, "Speed Sensor - Test" procedure in this manual to evaluate the Transmission Output Speed (TOS) sensor circuit. |
Ground speed and TOS are reading non-zero. Event Codes E2201-E2205 and/or E2301-E2303. |
NOT OK- If the ground speed or TOS is reading zero, or transmission slip events are occurring.
Repair: Follow the procedure described in Troubleshooting, "Speed Sensor - Test" procedure in this manual. Check and repair the speed sensor circuits. Upon completion of the procedure, confirm that the speed sensors are functioning correctly. Reset the"Transmission Main Relief Valve Compensation" through Cat ET after permanently replacing any components. OK- The ground speed is reading appropriately. NO transmission slip events occur. Return the machine to operation. STOP. |
Use the table and flow charts below to identify the clutches associated with the event codes for the "In Gear Slip Detect Feature".
Clutch engagement chart for machine models 950M and 962M:
| Speed Range and Direction | Engaged Clutches and Energized Solenoids |
| Fifth Speed Forward | 2 and 5 |
| Fourth Speed Forward | 1 and 5 |
| Third Speed Forward | 2 and 4 |
| Second Speed Forward | 1 and 4 |
| First Speed Forward | 1 and 6 |
| Neutral | 5 |
| First Speed Reverse | 3 and 6 |
| Second Speed Reverse | 3 and 4 |
| Third Speed Reverse | 3 and 5 |
Transmission Clutch Slips Troubleshooting Flow Chart
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| Illustration 2 | g03861785 |
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Flow Chart (Test Step 1) | |
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| Illustration 3 | g03861999 |
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Flow Chart (Test Step 2) | |
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| Illustration 4 | g03862002 |
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Flow Chart (Test Step 3) | |
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| Illustration 5 | g03862003 |
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Flow Chart (Test Steps 4 & 5) | |