My electronic 4 wheel drive has been acting up, sometimes it would shift in and work fine and sometimes not shift in....Two months ago it shifted into 4 wheel drive without me turning switch on dash and now will not shift out...I removed transfer case motor and shifted front dif. out...I replace GEM module under dash but that did not help...Has anyone had this problem or had a problem with there transfer case motor causing system to suddenly engage....I hate taking anything to a dealer. thanks for any input

 

Check this thread here. https://www.f150online.com/forums/sh...d.php?t=214177

It helped me and I posted my fix. Hope this helps.

 

I have a stupid question for you guys about the 4X4 system. I have a '98 4X4 with the manual shift lever on the transfer case. The question I have is: are the front drive axles suppose to disengage when the 4X4 is not engaged?
Most everyone on here talks about the vacuum module on the front diff, but I haven't heard anyone talk about the front axles.

 

The front axles on the 97-03 and 04 Heritage are always engaged. They are CV joints at the wheel. All engagement of the front diff is done at the diff by vacuum. The manual lever just engages the transfer case, not the front diff. So you are still using vacuum for the diff.

 

That's good to know, thanks for the info.

 

Exactly what king said. It is hard to believe that a little vacuum can be the difference between 4x4 and 4x2.