If only the rear wheels turn...I don't think you're stuck in 4wd. Do you have a locker in the front end that might be damaged? Also could be control arm bushings, ball joints, or something along those lines.
My old truck...a 2wd Dodge Dakota...had worn out balljoints and a loose control arm. It felt like I was driving a 4wd on dry pavement while making tight turns and skipped while turning. Replaced the balljoints and tightened up the control arm and voila...problem gone!