I noticed the past few days I've been in 4A due to icy/snowy conditions and my truck pulls somewhat hard to the right upon acceleration. It straightens out when I let off the gas and gets worse the more gas I give it. I don't have to FIGHT it to stay on the road but definitely have to counter-steer to keep straight. I also occasionally have a grinding from the front end if I accelerate from a stop (again in 4A) with wheels turned sharply. Are these two symptoms a sign of something going wrong in my front end?

 

sounds like you have a partially engaging IWE

 

This.

Jack up your front wheels and start the engine in 2H and then try to spin each of the front wheels (can be done one corner at a time if you need) and make sure both cv axles do not spin with the wheel.

 

Thanks yall. I will work on the troubleshooting this weekend. I read up a lot on the IWE system and most problems seem to be about NOT maintaining proper vacuum so the system partially gets into 4wd while driving, resulting in grinding, etc. Mine is the opposite where maybe an IWE (probably my passenger side) isn't engaging fully. I will start by just doing some wheel spinning, etc. to see if one of them looks different than the others.

 

Way late but 7 months later I finally replaced the IWEs while doing brakes. The front right was only partially engaging, as suspected. All gear teeth looked perfect but the top was engaging while the bottom wasn’t. Left side was fine but I went ahead and replaced both with new Motorcraft. Good call guys!