I have an '06 F-150 on my hoist in my garage and the woman is complaining that her 4WD is not engaging properly regardless of her dash lights coming on and saying that it is. Hence, she brought it here to be fixed. We have discovered that the vacuum system is functioning properly along with the transfer case is also engaging and working properly. Does anyone have any other input or suggestions that we can try to fix this vehicle before we ship it to a Ford Dealership?

 

Find a dirt or gravel road, stop and engage 4wd with her in the truck and goose the throttle quickly and let off, now get out and see if you have 4 skid marks in the dirt.

That should tell you and (Her most importantly) if the 4wd is working.

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