Spicer Tandem Drive Axles Service Manual D__R440, 460, 480, D_R461, 462, 463, 521, 581, 601, 651, 652, 653 User Manual
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Troubleshooting
Tr
oubleshooting
Check Electrical System
Check Solenoid Valve
1.
When ignition switch is “ON,” solenoid valve is ener-
gized and air pressure is available to operate the sys-
tem. When ignition switch is “OFF,” solenoid valve is
de-energized and exhausts the system which down-
shifts axle to low range. Check wiring and circuit
breaker for defects that would cause shorts or open
circuits.
2.
Make sure valve has a good ground connection to the
frame. With power at valve, check operation as fol-
lows:
•
Disconnect lead wire and airline outlet at valve
and install air pressure gauge.
•
Apply power to valve and observe air gauge
reading. Operating pressure should be approxi-
mate reservoir pressure.
•
If gauge indicates approximate pressure, valve is
okay.
•
If gauge indicates low or no pressure, valve is
faulty. Replace valve assembly.
Check Speedometer Adapter
1.
Make sure adapter is grounded to vehicle chassis.
2.
Check wiring for shorts or grounds and trace electri-
cal circuit from ignition switch through circuit break-
er, pressure switch to adapter.
3.
Check for power supply at adapter terminal. With axle
shifter valve in High Range, pressure switch is open
and power is not delivered to adapter. With shifter
valve in Low Range, the pressure switch is closed and
power is delivered to operate the speedometer adapt-
er. If power supply is okay, adapter is faulty. Replace
adapter assembly.