4A (transfer case)

OK, I'm going to ask the idiot question for the day.

4A, or Automatic 4wd. Has anyone used this and felt like the transfer case was engage the entire time?

I've driven Explorers in the past with 4A but don't remember how it felt. And today while driving to work (reports of black ice), I figured why not just toss it into 4A just in case. But if the rear tire isn't slipping, it shouldn't be engaging, though the steering felt stiffer (if that makes sense to you, the distinct feel while you are in 4wd). And it's not like you see 4x4 lit up on the dash when it engages (it just lit up 4A the entire drive).

Anyways, this is based on many many years of driving 2wd vehicles and 4x4's (mostly my full size Broncos of the past). And the feel of it was off. Not in a bad way, more of a curious way (as in, Am I in 4wd based on the feel?)