Front Axle Shift Motor Test
- Disconnect vacuum harness from front axle shift motor. Connect vacuum pump to shift motor front port. Apply 15 in. Hg vacuum to shift motor. Rotate right front wheel to disengage axle.
- Shift motor should hold vacuum at least 30 seconds. If not, replace motor. If motor does hold vacuum, disconnect vacuum pump from shift motor front port. Connect pump to shift motor rear port and cap transfer case connecting port. Apply 15 in. Hg vacuum to motor.
- Shift motor should hold vacuum for at least 30 seconds. If not, replace motor. If motor does hold vacuum, remove cap from shift motor transfer case connecting port and check for vacuum. If no vacuum is present, rotate right front wheel to ensure axle has shifted completely. Axle must completely shift to open shift motor connecting port.
- Recheck vacuum at shift motor transfer case port. If vacuum is present, transfer case requires diagnosis. Command-Trac uses Model 207 transfer case. Selec-Trac uses Model 228 transfer case.