Back in the summer while backing our camper in a space up hill, I had to use 4wd, I used low to have more power. When done, I shifted back to 2wd. The truck was stuck in low. We drove to the campground entrance and I stopped and pondered. I shifted to reverse and backed up 20 ft or so and it switched to 2wd. First time that has happened. It was also the first time I backed a heavy load up hill spinning a little.