Need some help with 4WD on my '05

[Dean Weiss]

Hello, I just signed up to get some help with my work truck. It's a 2005 Silverado 2500HD base model with the 6.0L auto and manual transfer case and has 280,000 kms. The issue I'm having is with the front axle actuator staying locked even with the transfer case in 2wd. I've had this issue for about a month now and previous google searches suggested that the actuator on the front axle might be the culprit so just today I tried replacing the actuator but that did not fix the problem. If I shift the transfer case into 4H and then back to 2H the dash light will go out briefly for a few seconds but then comes on again. Is there a sensor or switch on or inside the transfer case that might have gone bad? Is there a way to test the wiring from the transfer case to the axle actuator? I did notice a wiring plug near the linkage on the transfer case and I pulled it to check for corrosion or water or anything but it was clean and looked fine, I put in some dielectric grease and plugged it back in. The wiring plug into the axle actuator was clean and dry as well. I'm kind of out of ideas now and am hoping someone here may have had the same issue and knows of a fix. TIA

[davester]

The fix depends on what's wrong.  There's a sensor that screws into the transmission, that notices when it's in 4wd (either 4hi or 4lo, there's a separate sensor to notice hi or lo).  The sensor may have failed, there could be a wiring problem somewhere.  Diagnose, then replace parts/fix what's wrong...

[Formulabruce]

I have had to repair the wiring to the 4wd on or off sensor on WT's .

right at the sensor it can get brittle.