electric over air (eoa) range shift system diagnostics

TP-0776Revised 06-08

Technical Bulletin

Electric Over Air (EOA) Range Shift System Diagnostics

Platform “G” TransmissionsTP-0776Revised 06-081 Technical Bulletin

Hazard Alert MessagesRead and observe all Warning and Caution hazard alert messages in this publication. They provide information that can help prevent serious personal injury, damage to components, or both.

WARNINGTo prevent serious eye injury, always wear safe eye protection when you perform vehicle maintenance or service.

Park the vehicle on a level surface. Block the wheels to prevent the vehicle from moving. Support the vehicle with safety stands. Do not work under a vehicle supported only by jacks. Jacks can slip and fall over. Serious personal injury and damage to components can result.

How to Obtain Additional Maintenance and Service InformationRefer to Maintenance Manual MM-99106, 9- and 10-Speed Transmissions, Platform “G”. To obtain this publication, visit Literature on Demand at arvinmeritor.com.

How to Obtain PartsTo obtain the shift knob tester, part number J-44356, contact the SPX Kent-Moore service center at 800-345-2233.

How the Electric Over Air (EOA) Range Shift System WorksMeritor’s Electric Over Air (EOA) range shift system electronically controls the pneumatic actuation of the range shift through the use of an electronic shift lever, neutral switch and solenoids.

Components

Tools Required� Volt-ohm Meter

� Pressure Gauge

� Kent-Moore Shift Knob Tester, Part Number J-44356

Component Function

Shift Knob Transmission in Neutral: Activates the preselected range shift solenoid. Requires 12 VDC switched power.

Preselected high range: Activates the high range solenoid and deactivates the low range solenoid.

Preselected low range: Activates the low range solenoid and deactivates the high range solenoid.

High and Low Range Shift Solenoids

Performs as electronic valves that enable air to pass through only when activated by the shift knob. Requires 12 VDC switched power.

Neutral Switch Selecting Neutral closes the switch, activates the preselected range shift solenoid, and deactivates the other one.

Wiring Harnesses Connect components that operate the system.

TP-0776Revised 06-08 (16579/22882) Copyright ArvinMeritor, Inc., 2008 Printed in USA

DiagnosticsElectric Over Air (EOA) components are not serviceable. Replace components that do not function correctly.

In-Cab Diagnostics

Define the ProblemAsk the vehicle operator to describe the problem.

� When did you first notice the problem?

� Is the transmission making any noise? If so, when do you notice it most?

� What is the system air pressure?

� Have you noticed any other unusual gauge readings or electrical problems?

� Is the problem intermittent or constant?

Test drive the vehicle to verify the vehicle operator’s comments.

Vehicle Chassis Ground Test1. Turn the key switch to the OFF position with the engine off.

2. Move the shift lever into Neutral.

3. Remove the screw on the shift knob and separate the skirt from the shift knob.

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ONOFF

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TP-0776(16579/22882) Revised 06-08Printed in USA Copyright ArvinMeritor, Inc., 2008

4. Disconnect the four-pin connector at the shift knob.

5. Measure the resistance between Pin D of the four-pin connector and the vehicle negative battery terminal. Record the reading.

Resistance Pin D to Battery Ground: _____________

� If the resistance is greater than 0.5 ohm or is “OL”: Repair the vehicle ground system. Contact the vehicle manufacturer for diagnostic and repair assistance.

Vehicle Chassis Ground Test

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Vehicle Voltage Test1. Turn the key switch to the ON position with the engine off.


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ON

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5. Measure the voltage across Pins A and D, and Pins B and D. Record the voltage readings.

Voltage Pin A to Pin D: _____________

Voltage Pin B to Pin D: _____________

� If the voltage is less than 9 volts: Repair the vehicle electrical system. Contact the vehicle manufacturer to correct the voltage supply problem.

Vehicle Voltage Test

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DCV

MAXHOLD

OHMS

DCA

D

A

C

B

Neutral Switch Test1. Move the shift lever into Neutral.

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4. Test One

Measure the resistance (ohms) between Pins A and C of the four-pin connector. Place the red DVOM lead on Pin A and the black DVOM lead on Pin C. Record the reading.

Neutral Switch Pin A to Pin C: ________

� If the resistance is 0.1-0.5 ohm: The reading is within specification.

� If the resistance is “OL” or greater than 0.5 ohm: Check the neutral switch assembly and repair as necessary. When the repair is complete, repeat the test to ensure the neutral switch assembly functions correctly.

5. Move the shift lever into gear.

Neutral Switch Test

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D

A

C

– +

B

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6. Test Two

Measure the resistance (ohms) between Pins A and C. Place the red DVOM lead on Pin A and the black DVOM lead on Pin C. Record the reading.

Neutral Switch Pin A to Pin C: ________

� If the reading is “OL”: The neutral switch is functioning correctly.

� If the volt-ohm meter shows any resistance: Check the neutral switch assembly and repair as necessary. When the repair is complete, repeat the test to ensure the neutral switch assembly functions correctly.

Neutral Switch Test

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D

A

C

– +

B

Low Range Solenoid Test1. Remove the screw on the shift knob and separate the skirt from the

shift knob.

2. Disconnect the two-pin and four-pin connectors at the shift knob.

3. Measure the resistance (ohms) between Pin A of the two-pin connector and Pin D of the four-pin connector. Record the reading.

Resistance Pin A (two pin) to Pin D (four pin): ________

� If the resistance is 11-21 ohms: The low range solenoid is functioning correctly.

� If the resistance is less than 11 ohms or more than 21 ohms: Check the solenoid and wiring system and repair as necessary. When the repair is complete, repeat the test to ensure the solenoid is functioning correctly.

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AB

D

A

C

B


High Range Solenoid Test1. Remove the screw on the shift knob and separate the skirt from the

shift knob.


3. Measure the resistance (ohms) between Pin B of the two-pin connector and Pin D of the four-pin connector. Record the reading.

Resistance Pin B (two pin) to Pin D (four pin): ________

� If the resistance is 11-21 ohms: The high range solenoid is functioning correctly.

� If the resistance is less than 11 ohms or more than 21 ohms: Check the solenoid and wiring system and repair as necessary. When the repair is complete, repeat the test to ensure the solenoid is functioning correctly.

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AB

D

A

C

B

Shift Knob Testing — Visual Connector Check1. Remove the screw on the shift knob and separate the skirt from the

shift knob.

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2. Inspect the shift knob connectors. Verify that the connectors are seated correctly and the connector locks are engaged.


4. Inspect the pins on both sides of the connector for corrosion.

� If corrosion is found: Replace the component.

5. Inspect the pins on the female connector ends to ensure they are straight. If the pins are bent apart, they will not make sufficient contact with the male connector pins.

� If damage is found: Replace the component.

Shift Knob Testing — Visual Connector Check

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6. Inspect the male connector pins for damage.

� If damage is found: Replace the component.

Shift Knob Testing — Visual Connector Check

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Shift Knob Testing — Standard Shift Knob Test1. Obtain the SPX Kent-Moore shift knob tester, part number J-44356.

2. Connect the tester to the shift knob connectors.

3. Follow the directions on the tester to verify that the shift knob is functioning correctly.

� If the shift knob does not pass the test: Replace the shift knob.

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Shift Knob Testing — Overtravel Test1. Connect the tester to the shift knob connectors.

2. Set the tester to the In Neutral position.

3. Move the range selector to the Low position.

4. With the range selector in the Low position, push DOWN on the selector.

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5. Watch the test lights on the shift knob tester. Verify that the only light illuminated is the Low light.

� If the light flickers or the High light becomes illuminated: Replace the shift knob.

6. Lightly press UP 1/4-inch on the range selector, but do not change the range. Then press the selector back DOWN.

7. Watch the test lights on the shift knob tester. Verify that the only light illuminated is the Low light.

� If the light flickers or the High light becomes illuminated: Replace the shift knob.

8. Move the range selector into the High position.

Shift Knob Testing — Overtravel Test

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9. With the range selector in the High position, push UP on the selector.

10. Watch the test lights on the shift knob tester. Verify that the only light illuminated is the High light.

� If the light flickers or the Low light becomes illuminated: Replace the shift knob.

11. Lightly press DOWN 1/4-inch on the range selector, but do not change the range. Then press the selector back UP.

12. Watch the test lights on the shift knob tester. Verify that the only light illuminated is the High light.

� If the light flickers or the Low light becomes illuminated: Replace the shift knob.

Shift Knob Testing — Overtravel Test

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Shift Knob Testing — Twist Test1. Connect the tester to the shift knob connectors.



4. Grip the shift knob and rotate it in a twisting motion.

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5. Watch the tester to see if the light flickers or changes status.

� If any light change occurs: Replace the shift knob.

6. Grip the shift knob and push it forward and backward.

7. Watch the tester to see if the light flickers or changes status.

� If any light change occurs: Replace the shift knob.

Shift Knob Testing — Twist Test

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Shift Knob Testing — Hair Trigger1. Connect the tester to the shift knob connectors.

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3. Slowly move the range selector from High to Low.

4. Watch the light status on the tester. The light should change status approximately at the center of the range selector’s travel.

� If the light changes status only near the beginning or end of the movement: Replace the shift knob.

5. Slowly move the range selector from Low to High.

Shift Knob Testing — Hair Trigger

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6. Watch the light status on the tester. The light should change status approximately at the center of the range selector’s travel.

� If the light changes status only near the beginning or end of the movement: Replace the shift knob.

Shift Knob Testing — Hair Trigger

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Shift Knob Testing — Rattle Test1. Connect the tester to the shift knob connectors.



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4. While holding the tester, grab the shift lever below the shift knob.

5. Rapidly move the shift lever left and right to the full extent of travel.

6. Watch the shift knob tester for any light status changes.

� If the light flickers or the status changes: Replace the shift knob.

7. Rapidly move the shift lever forward and backward to the full extent of travel.

Shift Knob Testing — Rattle Test

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8. Watch the shift knob tester for any light status changes.

� If the light flickers or the status changes: Replace the shift knob.

Shift Knob Testing — Rattle Test

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Shift Knob Testing — Wire Pull Test1. Connect the tester to the shift lever connectors.


3. Gently pull on each wire. Use no more than 2 pounds (8.9 N) of force.

4. Verify the pin is seated correctly in the connector and is not loose.

� If the pin is loose: Replace the shift knob.

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5. Watch the tester light for any status change.

� If the light changes status: Replace the shift knob.

Shift Knob Testing — Wire Pull Test

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Intermittent System Test (Rapid)1. Build vehicle air pressure to the standard operating pressure.

2. Check that the key is in the ON position and the engine is off.

3. Ensure that the vehicle air pressure stays above 90 psi (6.2 bar) for the entire test procedure.

NOTE: If the pressure drops below 90 psi (6.2 bar), this test will not provide reliable results.

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100

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0

AIRPSI

P

100

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0

AIRPSI

S

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ON

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100

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0

AIRPSI

P

100

15060

0

AIRPSI

S

For reliable testresults, do not

let the airpressure

drop below90 psi

(6.2 bar).





7. Preselect a range change by moving the range selector to the High position. You should not hear the synchronizer activate while in gear.

Intermittent System Test (Rapid)

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8. Move the shift lever out of gear into Neutral.

9. Listen for the synchronizer to immediately move. The sound indicates the completion of the range change.

10. Repeat the range change steps for 50 actuations.

Move the shift lever out of gear into Neutral at a speed of approximately ONE SECOND per shift.

11. Record any occurrences where the range shift system did NOT activate when shifted from the gear to neutral.

Any observed delays or no shifts? _____________

� If all range shift actuations were observed immediately once the shift lever was moved to Neutral: The range shift system is operating correctly.

� If a range shift did not occur immediately once the shift lever was moved to Neutral: The Electric Over Air system is not functioning correctly. Identify and correct the root cause of the problem before you replace the synchronizer.

Intermittent System Test (Rapid)

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Intermittent System Test (Slow)1. Build vehicle air pressure to the standard operating pressure.

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100

15060

0

AIRPSI

P

100

15060

0

AIRPSI

S


2. Check that the key is in the ON position and the engine is off.

3. Ensure that the vehicle air pressure stays above 90 psi (6.2 bar) for the entire test procedure.

NOTE: If the pressure drops below 90 psi (6.2 bar), this test will not provide reliable results.



Intermittent System Test (Slow)

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ON

4006790b

100

15060

0

AIRPSI

P

100

15060

0

AIRPSI

S

For reliable testresults, do not

let the airpressure

drop below90 psi

(6.2 bar).

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7. Preselect a range change by moving the range selector to the High position. You should not hear the synchronizer activate while in gear.

8. Move the shift lever out of gear into Neutral.

9. Listen for the synchronizer to immediately move. The sound indicates the completion of the range change.

10. Repeat the range change steps for 50 actuations.

Move the shift lever out of gear into Neutral at a speed of approximately THREE SECONDS per shift.

11. Record any occurrences where the range shift system did NOT activate when shifted out of gear into Neutral.

Any observed delays or no shifts? _____________

� If all range shift actuations were observed immediately once the shift lever was moved into Neutral: The range shift system is operating correctly.

� If a range shift did not occur immediately once the shift lever was moved into Neutral: The Electric Over Air system is not functioning correctly. Identify and correct the root cause of the problem before you replace the synchronizer.

Intermittent System Test (Slow)

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Under-Cab Diagnostics

Vehicle Air Pressure Test1. Build vehicle air pressure to the standard operating pressure.

2. Turn the engine and key switch off and listen for air leaks underneath the vehicle.

� If air leaks are detected: Repair the leaks as necessary. When repairs are complete, repeat the test to ensure the system functions correctly.

3. Connect an air pressure gauge at the vehicle inlet air pressure port.

4. Build vehicle air pressure to the standard operating pressure.

5. Record the vehicle system air pressure.

Vehicle Air Pressure: ____________________

Verify that the system pressure is within the acceptable range. Refer to the vehicle manufacturer guidelines for your specific vehicle.

� If system pressure is not within the acceptable range: Repair the system. When repairs are complete, repeat the test to ensure the system functions correctly.

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100

15060

0

AIRPSI

P

100

15060

0

AIRPSI

S

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ONOFF

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REGULATEDAIR PRESSURE

PORTS

HIGHDIAGNOSTIC PORT

LOW DIAGNOSTIC PORT VEHICLEAIR SUPPLY —

Connect theair pressuregauge here.

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Regulated Air Pressure Test1. Connect an air pressure gauge to the regulated air pressure port on

the range piston housing.


3. Record the regulated air pressure.

Regulated Air Pressure: __________________

Verify that the regulated air pressure is 55-75 psi (3.79-5.17 bar).

� If the air pressure is not within this range: Check the air filter regulator for damage or contaminants. Replace the air filter regulator.

Low Diagnostic Air Pressure Test1. Connect an air pressure gauge to the low diagnostic port on the

range piston housing.

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REGULATEDAIR PRESSUREPORTS —

Connect theair pressuregauge here.

HIGHDIAGNOSTIC PORT

LOW DIAGNOSTIC PORT VEHICLEAIR SUPPLY

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0

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P

100

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0

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S

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REGULATEDAIR PRESSUREPORTS

HIGH DIAGNOSTICPORT

LOW DIAGNOSTIC PORT — Connect the air

pressure gauge here. VEHICLEAIR SUPPLY


2. Turn the key switch to the ON position and start the engine.




6. Record the pressure reading from the low diagnostic port.

Low Air Pressure: ____________________

Verify that the air pressure is 45-75 psi (3.1-5.17 bar).

� If the air pressure is low: Check for damage to the range piston housing, contaminants in the range piston housing, or a tear in the range piston or range shaft seal.

Low Diagnostic Air Pressure Test

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ON

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100

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0

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P

100

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0

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S

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High Diagnostic Air Pressure Test1. Connect an air pressure gauge to the high diagnostic port on the

range piston housing.

2. Turn the key switch to the ON position and start the engine.


4. Move the range selector to the High position.

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REGULATEDAIR PRESSUREPORTS

HIGH DIAGNOSTICPORT — Connect the air pressure gauge here.

LOW DIAGNOSTIC PORT VEHICLEAIR SUPPLY

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ON

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6. Record the pressure reading from the high diagnostic port.

High Air Pressure: ____________________

Verify that the air pressure is 45-75 psi (3.1-5.17 bar).

� If the pressure is low: Check for damage to the range piston housing, contaminants in the range piston housing, or a tear in the range piston.

High Diagnostic Air Pressure Test

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0

AIRPSI

P

100

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0

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S

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Information contained in this publication was in effect at the time the publication was approved for printing and is subject tochange without notice or liability. Meritor Heavy Vehicle Systems, LLC, reserves the right to revise the information presented orto discontinue the production of parts described at any time.

Copyright 2008 TP-0776ArvinMeritor, Inc. Revised 06-08All Rights Reserved Printed in USA (16579/22882)

Meritor Heavy Vehicle Systems, LLC2135 West Maple RoadTroy, MI 48084 USA800-535-5560arvinmeritor.com

electric over air (eoa) range shift system diagnostics

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