2004 Truck. Engine Size : 5.7 liter Question: 4x4 not working . Does not switch over when I try to engage it.

It would help if you mentioned the make and model of your vehicle, and if you have electronic 4WD, or have to shift it into 4WD manually. If it's electronic, you could have a bad switch, or a bad actuator on the front axle. Either electronic or manual, you could have a mechanical failure inside the front axle housing that is causing it not to engage into 4WD, like broken gears or axles, mis-aligned parts, etc. If the problem is with the transfer case, you could have a bad encoder motor or a mechanical failure inside the transfer case. On the electronically controlled systems, there is a main control module that could be bad as well. You're best bet is to get it to a shop for diagnosis.


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    • dave

      I have a 2005 GMC Sierra 1500 Z71 with electronic 4wd. When I press 4w high, the light selector works and goes to high, but the 4wd is not engaged (the front tires do not spin)? I checked the fuse and its good. Any ideas? I hear a slight electrical noise when I go to high and a clunk when I go to low but it doesn't engage.

    • Tech

      In reply to: dave

      Since you hear it tying to engage, then you could have a bad encoder motor. This is on the transfercase and is what changes gears, or an internal problem in the case that does not allow it to change.

    • Ira

      I have a 1992 GMC Sierra 4x4 that won't go into 4x4. There seems to be no power going to the front axel actuator. The actuator does work, tested ok. How can I test the switch on the transfer case?


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