651E and 657E Wheel Tractor-Scrapers Power train Power Train Troubleshooting Caterpillar

Note: Before performing the checks, refer to Systems Operation/Testing and Adjusting, "Machine Preparation for Troubleshooting".

Check 1

This check will determine if the rotary actuator and the rotary selector spool can operate without the electrical system or hydraulic systems.

Procedure for Manual Shifting

Illustration 1	g00699383
Plug for the Rotary Selector Spool (Right Side of Transmission)

When you are troubleshooting the power train, it may be necessary to shift the transmission. This procedure is performed manually by turning the rotary selector spool when the engine is OFF.

1. Remove the plug for the rotary selector spool.

2. Install a 1/4 inch socket extension, that is four inches long, in the end of the rotary selector spool. Install a 1/4 inch ratchet on the extension.

3. Turn the rotary selector spool in a clockwise direction as far as possible by using the ratchet. This is the NEUTRAL position.

4. Turn the rotary selector spool in a counterclockwise direction through all the speed positions by using the ratchet. There is approximately 30 degrees of rotation between each detent of the rotary selector spool. The following list shows the order of the detent position:

• NEUTRAL

• REVERSE

• FIRST SPEED

• SECOND SPEED

• THIRD SPEED

• FOURTH SPEED

• FIFTH SPEED

• SIXTH SPEED

• SEVENTH SPEED

• EIGHTH SPEED

Procedure

Machine condition: DO NOT START THE ENGINE. THE ENGINE START SWITCH IS IN THE OFF POSITION.

1. Prepare to manually shift the transmission.

2. Manually shift the transmission through all speed positions.

3. Turn the rotary selector spool to the NEUTRAL position.

Results

• The rotary selector spool rotates through all speed selections. Refer to Service Manual, SENR9122, "Electronic Programmable Transmission Control (EPTC II) for ICM Transmissions" for additional information.

• If the rotary selector spool does NOT rotate through all the speed positions, check for the following conditions:

• Detent springs on the rotary selector spool are bent.

• The detent springs on the rotary selector spool are broken.

• Foreign material or a damaged component does not permit movement of the rotary selector spool.

• Foreign material does not permit movement of the rotary actuator.

Check 2

This check will determine the following conditions:

• The electrical signal is delivered to the downshift solenoid.

• The downshift solenoid activates electrically.

• The ground verify wires are connected to the machine ground.

Procedure

Machine condition: THE ENGINE IS IN THE OFF POSITION. THE ENGINE SWITCH KEY IS IN THE ON POSITION.

1. Position the transmission shift lever and the tractor transmission rotary selector lever in NEUTRAL. DO NOT START THE ENGINE.

2. Disconnect the harness connector for the downshift solenoid from the downshift solenoid.

3. Make contact with the harness connector for the downshift solenoid to the downshift solenoid. When the connector makes contact to the downshift solenoid, a clicking or a buzzing noise will occur.

4. When the check is complete, connect the harness connector for the downshift solenoid to the downshift solenoid.

Results

• If the click is heard or the buzz is felt, then proceed to "Check 3".

If there are no clicking or buzzing, perform the following checks:

• Check that the downshift solenoid is not bad.

• Check the ground verify wires in order to ensure that there are no electrical problems. Refer to Service Manual, SENR9122, "Electronic Programmable Transmission Control (EPTC II) for ICM Transmissions.".

• Check the wire to the downshift solenoid in order to ensure that the wire is not open or broken. Refer to Service Manual, SENR9122, "Electronic Programmable Transmission Control (EPTC II) for ICM Transmissions.".

• Check the harness to the downshift solenoid in order to ensure that the harness is not open or broken. Refer to Service Manual, SENR9122, "Electronic Programmable Transmission Control (EPTC II) for ICM Transmissions.".

Check 3

This check will determine the following conditions:

• The Electrical signal is delivered to the upshift solenoid.

• The upshift solenoid activates electrically.

• The ground verify wires are connected to the machine ground.

Procedure

Machine Condition: THE ENGINE IS IN THE OFF POSITION. THE ENGINE START SWITCH KEY IS IN THE ON POSITION.

1. Maintain the conditions that were stated in "Check 2":
   • The transmission control is in the NEUTRAL position.

   • The rotary selector spool is in the NEUTRAL position.

   • The battery disconnect switch is in the ON position.

   • The engine start switch is in the ON position.

   • DO NOT START THE ENGINE.

2. Place the transmission shift lever in REVERSE.

3. Disconnect the harness connector for the upshift solenoid from the upshift solenoid.

4. Make contact with the harness connector for the upshift solenoid to the upshift solenoid. When the connector makes contact to the downshift solenoid, a clicking or a buzzing noise will occur.

5. When this check is complete, connect the harness connector for the upshift solenoid to the upshift solenoid. Place the transmission shift lever in NEUTRAL.

Results

• If a clicking or a buzzing occurs, refer to Service Manual, SENR9122, "Electronic Programmable Transmission Control (EPTC II) for ICM Transmissions".

If a clicking or a buzzing does not occur, perform the following checks:

• Check that the downshift solenoid is not bad.

• Check the ground verify wire in order to ensure that the wire is not open or broken. Refer to Service Manual, SENR9122, "Electronic Programmable Transmission Control (EPTC II) for ICM Transmissions".

• Check if the wire to the upshift solenoid is open or broken. Refer to Service Manual, SENR9122, "Electronic Programmable Transmission Control (EPTC II) for ICM Transmissions".

• Check if the harness to the upshift solenoid is open or broken. Refer to Service Manual, SENR9122, "Electronic Programmable Transmission Control (EPTC II) for ICM Transmissions".

Check 4

This check will determine if the tachometer is operating properly.

Illustration 2	g00420584
9U-7400 Multitach Tool Group

Some of the operational checks use the tachometer. If the tachometer does not operate correctly, replace the tachometer or use 9U-7400 Multitach Tool Group .

9U-7400 Multitach Tool Group measures the engine speed by the use of one of the following tools:

• Photo pickup and reflective tape

• Magnetic pickup

• Tachometer generator

Instructions for the uses are provided in the case.

Procedure

Note: Before this procedure is started, refer to the "WARNINGS" label in Systems Operation, Testing and Adjusting, "Machine Preparation for Troubleshooting".

Machine condition: THE transmission shift lever AND THE TRACTOR TRANSMISSION ROTARY SELECTOR LEVER IS IN THE NEUTRAL POSITION. THE ENGINE IS OPERATING AND THE ENGINE START SWITCH KEY IS IN THE ON POSITION.

1. Operate the engine at LOW IDLE.

2. Check the tachometer in order to ensure that the tachometer is operating properly. As the accelerator pedal is depressed, an increase in engine rpm must be displayed at the tachometer.

Results

• If the tachometer does not operate correctly, the tachometer or tachometer drive unit is bad. Refer to Schematic, SENR9092, " 651E Wheel Tractor-Scraper, Electrical System" and Schematic, SENR9093, " 657E Wheel Tractor-Scraper Electrical System" for the electrical components and locations.

Check 5

This check will determine the following conditions:

• The differential lock will properly engage.

• The differential lock will properly release.

• The steering relief valve properly works.

Procedure

Note: Before this procedure is started, refer to the "WARNINGS" in Systems Operation, Testing and Adjusting, "Machine Preparation for Troubleshooting".

Machine condition: THE ENGINE IS OPERATING AND THE ENGINE START SWITCH KEY IS IN THE ON POSITION.

1. Maintain the conditions that are found in "Check 4".
   • The transmission shift lever is in NEUTRAL.

   • The tractor transmission rotary selector lever is in NEUTRAL.

   • The battery disconnect switch and the engine start switch key is in the ON position and the engine is operating.

2. Release the parking brakes by depressing the control knob for the parking and secondary brake.

3. Raise the empty scraper bowl.

4. While the engine is operating at LOW IDLE rpm, turn the wheels all the way to the left. You should then turn the wheels to the right.

5. While the wheel tractor and the scraper is in a straight position, depress the differential lock switch and hold the differential lock switch.

6. Turn the steering wheel for a left turn. Then turn the steering for a right turn. The machine must not make a complete left turn or a complete right turn.

7. Release the differential lock switch.

8. Turn the steering wheel for a left turn. Then turn the steering wheel for a right turn. The machine must make a complete left turn or a complete right turn.

9. Engage the parking brakes and lower the empty scraper bowl.

Results

• If the machine passes the tests in step 6 and step 8, then proceed to "Check 6".

• If the machine does not turn, the steering system is bad. Refer to Systems Operation, Testing and Adjusting, SENR9082, " 651E Wheel Tractor-Scraper, 657E Wheel Tractor-Scraper Steering System".

While the differential lock is engaged and the machine makes a complete turn right and left, perform the following checks:

• Wear or damage to the differential lock switch or solenoid

• Check the differential lock solenoid in order to ensure that there is no pressure air. Check the quick release valve in order to ensure that there is no pressure air. Check the differential lock cylinder in order to ensure that there is no pressure air. Refer to Systems Operation, Testing and Adjusting, SENR9084, " 651E Wheel Tractor-Scraper, 657E Wheel Tractor-Scraper Air System and Brakes".

• Check the quick release valve for wear or damage. Refer to Systems Operation, Testing and Adjusting, SENR9084, " 651E Wheel Tractor-Scraper, 657E Wheel Tractor-Scraper Air System and Brakes".

• Check the differential lock cylinder in the differential for wear or damage.

While the differential lock is disengaged and the machine is not making a complete turn, perform the following checks:

• Wear or damage to the differential lock switch or solenoid

• Check the differential lock solenoid in order to ensure that there is no pressure air. Check the quick release valve in order to ensure that there is no pressure air. Check the differential lock cylinder in order to ensure that there is no pressure air. Refer to Systems Operation, Testing and Adjusting, SENR9084, " 651E Wheel Tractor-Scraper, 657E Wheel Tractor-Scraper Air System and Brakes".

• Check the quick release valve for wear or damage. Refer to Systems Operation, Testing and Adjusting, SENR9084, " 651E Wheel Tractor-Scraper, 657E Wheel Tractor-Scraper Air System and Brakes".

• Check the differential lock cylinder in the differential for wear or damage.

Check 6

The check will determine the following conditions:

• The engine performance is good.

• The retarder (if equipped) properly engages.

• The retarder (if equipped) properly releases.

• The air pressure for the retarder (if equipped) is good.

• The oil pressure for the retarder (if equipped) is good.

Procedure

Note: Before this procedure is started, refer to the "WARNINGS" in Systems Operation, Testing and Adjusting, "Machine Preparation for Troubleshooting".

Machine condition: THE ENGINE IS OPERATING AND THE ENGINE START SWITCH KEY IS IN THE ON POSITION.

1. Maintain the conditions that are in "Check 5":
   • The transmission shift lever and the tractor transmission rotary selector lever is in NEUTRAL.

   • The battery disconnect switch and the engine start switch key is in the ON position. The engine is operating.

2. Operate the engine at HIGH IDLE.

Show/hide table

NOTICE
Be sure that the torque converter (transmission) oil does not get too hot.

3. Engage the retarder brakes (if equipped) by pulling the retarder control lever away from the operator. The engine rpm decreases to 1850 rpm ± 100 rpm.

   Note: Running the machine in this condition for an extended period of time will cause critical engine overheating.

4. Release the retarder brakes (if equipped) by pushing the retarder control lever away from the operator. The engine rpm must return to the original HIGH IDLE rpm.

5. When this check is complete, return the engine to the LOW IDLE speed.

Results

• If the engine rpm meets the criteria in step 3 and step 4, refer to the Service Manual, SENR9122, "Electronic Programmable Transmission Control (EPTC II) for ICM Transmissions". This will determine if the transmission output speed sensor is operating properly.

• While the retarder control lever is in the FULLY ACTIVATED position, the engine rpm does not decrease. The retarder does not engage. Refer to Systems Operation, Testing and Adjusting, "Retarder Operation - Test".

• When the retarder control lever is moved from the FULLY ACTIVATED position to the RELEASED position, engine rpm does NOT increase. The retarder does NOT release. Refer to Systems Operation, Testing and Adjusting, "Retarder Operation - Test".

Check 7

This check will determine the following conditions:

• The output speed sensor for the engine is operating properly for upshifts through FOURTH speed.

• Automatic upshifts from SECOND through FOURTH speeds of the transmission control are correct.

• The transmission hydraulic controls operate during upshifts through SECOND, THIRD and FOURTH speeds.

Procedure

Note: Before this procedure is started, refer to the "WARNINGS" in Systems Operation, Testing and Adjusting, "Machine Preparation for Troubleshooting".

Machine condition: ROAD THE MACHINE.

1. Start the engine and operate the engine at LOW IDLE rpm.

2. Engage the service brakes. Release the parking and secondary brakes.

3. Place the transmission shift lever in FIRST speed.

4. Increase the machine ground speed and place the transmission shift lever in FOURTH speed.

The transmission manually shifts to SECOND speed as the transmission shift lever is moved toward the FOURTH speed position. As the ground speed of the machine increases, the transmission automatically shifts into THIRD speed. The machine then continues to shift into FOURTH speed. The transmission upshifts from THIRD speed to FOURTH speed at approximately 2020 engine rpm.

Results

• If the transmission does not automatically upshift at approximately 2020 engine rpm or if the transmission does not automatically upshift, refer to Service Manual, SENR9122, "Electronic Programmable Transmission Control (EPTC II) for ICM Transmissions". This will determine if the output speed sensor for the engine is operating properly.

• If the transmission upshifts, but the ground speed of the machine does not increase, then the hydraulic system is bad. If the transmission upshifts and the machine is coasting without power, then the hydraulic system is bad. Perform the Systems Operation, Testing and Adjusting, "Transmission Hydraulic Control Maximum Clutch Pressure - Test".

Check 8

This check inspects all the power train components.

Final drive - Drain the covers and remove the covers. Inspect the covers for damages.

Bevel gear, pinion and differential - Raise one wheel of the machine off the ground. Turn the wheel forward and turn the wheel backward in order to check for backlash in the differential. For the correct amount of backlash, refer to Specifications, SENR9071, " 651E Wheel Tractor-Scraper, 657E Wheel Tractor-Scraper Power Train".