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4wd Stuck, Won't Switch To 2wd

BigSilver

By BigSilver
in Ask A GM Technician

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BigSilver Enthusiast

BigSilver

Posted
Posted

Perhaps someone is familiar with a similar 4wd glitch.

 

I just picked up a 2nd hand 2003 Chevy Suburban 2500 and according to the dash board buttons it operates in either Auto 4wd, Hi4wd, or Lo4wd.

 

Now I've read many postings about replacing the front axel actuator. So I replaced mine hoping 2WD would begin working. No luck. After pressing the 2WD button, the respective light would flash a couple of times, a clicking sound would emanate from the transfer case's encoder motor, and finally after the clicking would stop, the 4WD button's light would illuminate.

 

One thing I did notice though, when I disconnected the wire harness to the front axel actuator and turned the ignition on, the 2WD light came on, without even pressing the 2WD button. Could this mean then that the transfer case's encoder motor is the root of the problem? Photos of my transfer case and encoder motor attached.

http://www.flickr.com/photos/13753819@N02/2555587250/

Is this component (partly) serviceable?

 

Could this mean the transfer case's encoder is stuck?

 

Any thoughts?

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copenhagen Enthusiast

copenhagen

Posted
Posted

First thing, check your grounds. Their is 2 by the firewall, both connected to the engine

 

Check if their is corrosion between the tcase and the shifter motor..

 

Sometimes the module craps out and isnt cheap to replace

If you have a power probe, ground out (forget which wire?) and if it goes to 2wd then theirs a bad ground or the module is bad.. your switch and encoder seems to be working ok

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