Troubleshooting

Troubleshooting can be difficult. On the following pages there is a list of possible problems. To make a repair to a problem, make reference to the cause and correction.

This list of problems, causes and corrections will only give an indication of where a possible problem can be, and what repairs are needed. Normally, more of other repair work is needed beyond the recommendations in the list. Remember that a problem is not normally caused only by one part, but by the relation of one part with other parts. This list can not give all possible problems and corrections. The serviceman must find the problem and its source, then make the necessary repairs.

1. Contactor Switch for Water Temperature fails to Activate Shutoff.

2. Contactor Switch for Water Temperature Activates Shutoff at Wrong Temperature.

3. Switch for Oil Pressure Fails to Activate Shutoff.

4. Engine Protection Panel Will Not Activate Engine Shutoff.

5. Engine Protection Panel Stops Engine When Reset Button is Released.

6. Clutch Will Not Engage (Slips), Heats or Lever Moves to Released Position.

7. Clutch Shaft Has Too Much End Play.

8. Electrical Gauges Give Wrong Readings.

Contactor Switch For Water Temperature Fails To Activate Shutoff

Contactor Switch For Water Temperature Activates Shutoff At Wrong Temperature

Switch For Oil Pressure Fails To Activate Shutoff

Engine Protection Panel Will Not Activate Engine Shutoff

Engine Protection Panel Stops Engine When Reset Button Is Released

Clutch Will Not Engage (Slips), Or Lever Moves To Released Position

Clutch Shaft Has Too Much End Play

Electrical Gauges Give Wrong Readings

Electrical System

Contactor Switch For Water Temperature

Fabricated heat sink.2F7112 Thermometer.3J5389 Plug.8S4627 Circuit Tester.

First Method of Checking

1. Make a heat sink as shown. Material can be brass, steel or cast iron. Drill a 23/32 in. hole through the plate and use a tap to make 1/2 in. NPT threads.

2. Put marks on wire connections to contactor terminals and disconnect wire.

HEAT SINK [Dimensions in inches (mm)]

TEST OF CONTACTOR SWITCH
1. 2F7112 Thermometer. 2. Fabricated heat sink.

3. Remove the contactor and install a 3J5389 Plug. Install the contactor switch in the heat sink.

4. Connect the wires to the contactor switch to check all of the system; contactor switch, wires, etc.

NOTE: If the wires can not be disconnected, use the second method of testing.

5. When the contactor switch is connected again, start the engine and run it at low idle rpm. The pressure switch will complete the circuit when the engine is running.

NOTE: When applying heat to the water in Step 6, be sure to stir (keep water moving) while heating.

6. Put the heat sink and contactor element in water. Use blocks to support the heat sink at surface level. Use a torch to make the water hot and read the temperature on thermometer (1) at which the engine stops (switch is closed). For the 5L6435 Contactor, the temperature should be 209 ± 1 ° F (98 ± 0.6 ° C). Let the water temperature go down. The contactor switch will open when the temperature is 12 ° F (8 ° C) lower than the temperature at which the contactor closes.

7. Install new contactor switch if necessary.

To check other components in the system, put a jumper wire between C and NO terminals of the contactor switch for water temperature.

Second Method of Checking

1. Remove the wires from the contactor switch.

2. Connect the 8S4627 Circuit Tester between the C and NO terminals.

3. Start the engine and get it hot by making a reduction in coolant flow or air flow through the radiator. Temperature must not go more than approximately 3 ° above the maximum.

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NOTICE
If the engine can not be run safely at these high temperatures, the contactor must be checked off the engine.

4. Look at the circuit tester to see when the contactor switch closes. The light will be activated. The temperature must be 209 ± 1 ° F (98 ± 0.6 ° C) for the standard sea level contactor.

5. Let the engine run to slow cooling and then stop the engine.

6. Install new contactor switch if needed and connect wires to the contactor switch.

Electrical Gauges And Sending Units

Source for hydraulic pressure.5P6225 Hydraulic Test Box.Ohmmeter.2F7112 Thermometer.Heat sink. See contactor switch for water temperature.

Remember that the electrical gauges and sending units are to operate in electrical balance. For this reason, the voltage and resistance ratings are important to get the correct indications on the gauges.

Sending Units for Oil Pressure

SENDING UNIT FOR OIL PRESSURE
1. Terminal. 2. Fitting.

The sending unit for engine oil pressure can be checked for resistance to find if it is operating correctly. Connect the sending unit to a pressure source that can be measured with accuracy. Connect the ohmmeter between fitting (2) and terminal (1). Take resistance readings at the pressures shown.

If the test performance is correct for the sending unit for the oil pressure, install a new gauge.

Sending Unit for Water Temperature

A resistance check can be made to find if the sending unit is operating correctly. Connect an ohmmeter between nut (2) and terminal (1). Put bulb (3) in a pan of water. Use a torch to make the water hot. Put a thermometer in the water to measure the temperature. Take resistance readings at the temperature shown.

Refer to CONTACTOR SWITCH FOR WATER TEMPERATURE for heat sink and heat bath use.

SENDING UNIT FOR WATER TEMPERATURE
1. Terminal. 2. Nut. 3. Bulb.

If the test performance is correct for the sending unit for the water temperature, install a new gauge.

Electrical Gauges

To check the gauge, use the voltage shown as the test voltage. Install a resistance of the value shown, into the supply from the voltage source and connect the ground to the frame of the gauge. The indicator of the gauge should point to the temperature or pressure value given in the chart. The test must be made when the gauge is installed at the angle of 30° back from vertical position.

DIRECT READING GAUGE FOR WATER TEMPERATURE

2N781 GAUGE FOR ENGINE OIL PRESSURE

Power Take-Off Clutches

Clutch Adjustment

CLUTCH ADJUSTMENT
1. Lock pin (push-type). 2. Lock pin (pull-type).

1. Disconnect linkage (if so equipped) from the clutch lever. Fasten a spring scale to the clutch lever at the distance, from the lever shaft center, shown in the chart.

2. Look at the spring scale. Keep the angle between the scale and the lever at 90°. Pull the lever with the spring scale until the clutch engages. Make reference to the chart to find the correct amount of pull for the clutch assembly.

3. If the pull needed to engage the clutch is not correct, make an adjustment as follows:

4. Remove the inspection plate from the clutch housing.

5. Turn the clutch until lock pin (1 or 2) can be seen.

6. Release push-type lock pin (1) or pull type lock pin (2). Turn the adjustment ring and check the pull needed to engage the clutch again.

NOTE: Turn the adjustment ring clockwise, as seen from the rear of the clutch, to increase the pull needed. Turn it counterclockwise to decrease the pull needed.

Installation of Wear Sleeve

Clutch shaft bearings that have oil lubrication are equipped with wear sleeves (2). Install wear sleeves with guide assembly (1) (part of 1P2410 Wear Sleeve Installation Tool Group). Make sure the sleeve fits the shoulder fillets (3) on the shaft.

WEAR SLEEVE INSTALLATION
1. Guide assembly. 2. Wear sleeve. 3. Shaft shoulder fillets.

Assembly Adjustments

End Play for Shaft Bearings

1. With dry bearings installed on the shaft, install the shaft in the housing.

2. Install the retainer. Tighten the retainer (nut or shim-type) until 60 lb. in. (7 N·m) is needed to keep the shaft in rotation.

3. With shim-type retainer, measure the space between the retainer and the carrier. Add .013 in. (0.33 mm) to this measurement. Install this amount of shims between the retainer and the carrier. With nut-type retainers, turn it out the number of notches shown on the chart.

4. Hit the output end of the clutch shaft with a soft hammer. This will cause the front bearing cup to move against the retainer.

5. Check the shaft end play with a dial indicator. If necessary, add or subtract shims; or turn nut to get the correct end play.

Hub Nut Installation

1. Tighten the hub nut to a torque of 30 lb. ft. (40 N·m).

2. Tighten the nut more according to the chart.

Flywheel And Flywheel Housing Alignment

At the time of installation, check the flywheel and flywheel housing face and bore run out.

Check crankshaft end play after the clutch is installed.

Allison Transmission Mounting Group Alignment

8S2328 Dial Indicator Group.

To help prevent a failure to the flexplate, the flywheel housing spacer and the transmission adapter must be in correct alignment with the crankshaft.

NOTE: The flywheel housing and flywheel runout must be acceptable before the transmission mounting group is installed.

Face Runout (axial eccentricity) of the Flywheel Housing Spacer

1. Install the transmission adapter and flex plate on the flywheel. Tighten the bolts to 55 ± 5 lb. ft. (75 ± 7 N·m). Install the flywheel housing spacer on the flywheel housing.

2. Fasten a dial indicator to the transmission adapter and position the indicator so the anvil touches the face of the flywheel housing spacer.

8S2328 DIAL INDICATOR GROUP INSTALLED

3. Move the crankshaft to the rear to remove all end clearance before a reading is taken at each point.

4. Set the dial indicator to .000 in. at location (A), turn the crankshaft and read the indicator at locations (B), (C) and (D).

CHECKING FACE RUNOUT OF THE FLYWHEEL HOUSING SPACER
A. Bottom. B. Right side. C. Top. D. Left side.

5. The difference between positive (+) and negative (-) measurements taken at all four points must not be more than .008 in. (0.20 mm) for AT540 Transmission and .020 in. (0.51 mm) for MT643 and MT653 Transmissions.

Bore Runout (radial eccentricity) of the Flywheel Housing Spacer

8S2328 DIAL INDICATOR GROUP INSTALLED

1. Fasten a dial indicator to the transmission adapter and position the indicator so the anvil touches the large bore of the flywheel housing spacer.

2. With the dial indicator in position at (C), adjust the dial indicator to .000 in. Push the crankshaft up against the top bearing. Write the measurement for bearing clearance on Line 1 in column (C).

3. Divide the measurement from Step 1 by 2. Write this number on Line 1 in columns (B) & (D).

CHECKING BORE RUNOUT OF THE FLYWHEEL HOUSING SPACER

4. Turn the crankshaft to put the dial indicator at (A). Adjust the dial indicator to .000 in.

5. Turn the crankshaft counterclockwise to put the dial indicator at (B). Write the measurement in the chart.

NOTE: Write the dial indicator measurements with their positive (+) and negative (-) notation (signs). This is necessary for making the calculations in the chart correctly.

6. Turn the crankshaft counterclockwise to put the dial indicator at (C). Write the measurement in the chart.

7. Turn the crankshaft counterclockwise to put the dial indicator at (D). Write the measurement in the chart.

8. Add Lines I & II by columns.

9. Subtract the smaller number from the larger number in Line III in columns (B) & (D). The result is the horizontal "eccentricity" (out of round). Line III, column (C) is the vertical eccentricity.

10. On the graph for total eccentricity find the point of intersection of the lines for vertical eccentricity and horizontal eccentricity.

GRAPH FOR TOTAL ECCENTRICITY FOR AT540 TRANSMISSION

GRAPH FOR TOTAL ECCENTRICITY FOR MT643 AND MT653 TRANSMISSION

11. If the point of intersection is in the range marked "Acceptable" the bore is in alignment. If the point of intersection is in the range marked "Not Acceptable", remove the spacer and check the bore in the flywheel housing for dirt or damage.

Bore Runout (radial eccentricity) of the Transmission Adapter

1. Fasten the dial indicator to the flywheel housing and position the indicator so the anvil touches the bore of the transmission adapter.

2. Adjust the dial indicator to read .000 in. Turn the flywheel and read the indicator every 90°.

3. The difference between positive (+) and negative (-) measurements taken at all four locations must not be more than .010 in. (0.25 mm) for AT540 Transmissions and .005 in. (0.13 mm) for MT643 and MT653 Transmissions.

8S2328 DIAL INDICATOR GROUP INSTALLED

Face Runout (axial eccentricity) of the Transmission Adapter

1. Fasten the dial indicator to the flywheel housing and position the indicator so the anvil touches the face of the flex plate 3.00 in. (76.2 mm) from the center of the transmission adapter bore.

8S2328 DIAL INDICATOR GROUP INSTALLED

2. Move the crankshaft to the rear to remove all end clearance before a reading is taken at each location.

3. Adjust the dial indicator to read .000 in. Turn the flywheel and read the indicator every 90°.

4. The difference between the positive (+) and negative (-) measurements taken at all four locations must be .003 in. (0.08 mm) for AT540, MT643 and MT653 Transmissions.

Face Runout (axial eccentricity) of the Flex Plate

8S2328 DIAL INDICATOR GROUP INSTALLED

1. Fasten the dial indicator to the flywheel housing and position the indicator so the anvil touches the face of the flex plate at the large diameter bolt circle.

2. Turn the crankshaft to position the indicator anvil next to one of the bolts on the large diameter of the flex plate. Move the crankshaft to the rear to remove all end clearance before a reading is taken at each location.

3. Adjust the dial indicator to read .000 in. (0.00 mm). Turn the flywheel and read the indicator at a location next to each bolt on the large diameter of the flex plate.

4. The difference between the positive (+) and negative (-) measurements taken at all locations must not be more than .030 in. (0.76 mm) for AT540, MT643 and MT653 Transmissions.

Pulley Assemblies

Procedure For Assembling Fan Mounting Pulley Assembly

1. Install bearing cups (3 and 5) in pulley (1).

2. Put 2S3230 Bearing Lubricant in bearing cone (4).

TYPICAL PULLEY
1. Pulley. 2. Seal. 3. Bearing cup. 4. Bearing cone. 5. Bearing cup.

3. Install bearing cone (4) in bearing cup (5).

4. Install seal (2) in pulley (1). Be sure the sealing lip of seal (2) is toward bearing cone (4). Put a small amount of 2S3230 Bearing Lubricant on the lip of seal (2).

TYPICAL PULLEY ASSEMBLY WITH HEXAGON NUT AND PINNED SHAFT
1. Pulley. 2. Seal. 3. Bearing cup. 4. Bearing cone. 5. Bearing cup. 6. Sleeve. 7. Bearing cone. 8. Shaft. 9. Hexagon nut. 11. Washer. 12. Spacer. 15. Pin. A. Area to put lubricant.

5. Install sleeve (6) and pulley (1) on shaft (8).

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NOTICE
Do not damage the sealing lip of seal (2) when putting the pulley on the shaft.

6. Install the 4N7950 Spacer (12) on shaft (8). The 4N7950 Spacer is .440 ± .001 in. (11.18 ± 0.03 mm) long.

7. Put 2S3230 Bearing Lubricant around spacer (12) until area (A) is one-third to one-half full of lubricant.

8. Put 2S3230 Bearing Lubricant in bearing cone (7) and install the bearing in bearing cup (3).

9. Install washer (11) and nut (9).

10. Tighten nut (9) to 110 ± 15 lb. ft. (149 ± 20 N·m).

11. After the nut is tightened, check the end clearance of pulley (1). The pulley must have .001 to .010 in. (0.03 to 0.25 mm) end clearance.

12. If the end clearance is less than .001 in. (0.03 mm), remove the 4N7950 Spacer (12) and install a 4N7951 Spacer. the 4N7951 Spacer is .450 ± .001 in. (11.43 ± 0.03 mm) long. Assemble the pulley and again check end clearance. If the original end clearance is more than .010 in. (0.25 mm), remove the 4N7950 Spacer and install a 4N7949 Spacer. The 7N7949 Spacer is .430 ± .001 in. (10.92 ± 0.03 mm) long.

NOTE: Be sure to put 2S3230 Bearing Lubricant around the new spacer so area (A) is one-third to one-half full of lubricant. Always put more lubricant in bearing cone (7) before installing in bearing cup (3).

13. Install the remainder of the parts and tighten nut (9) to 110 ± 15 lb. ft. (149 ± 20 N·m). Check the end clearance again to be sure it is correct.

14. Put 2S3230 Bearing Lubricant in area (B). Area (B) mst be a minimum of one-third to one-half full of lubricant.

15. For 6N7691 and 8N8603 Pulley Assemblies, install gasket (24), hub (22), and bolts (23). Tighten bolts (23) to 18 ± 5 lb. ft. (24 ± 7 N·m).

6N7691 PULLEY ASSEMBLY
9. Nut. 22. Hub. 23. Bolts. 24. Gasket. B. Area to put lubricant.