today i was driving in snow and i was on ice and the rear wheels spun and i stoped compeltly and put it in 4x4 hi and it made a griding noise when i barely hit the gas so i get off the gas and hit the brake and hit the gas again and it did it again then it when clunk and it was engaged i think its nornal but i know your not soppesed to engage it when the tires are spinning and i never have done tht but tht is what it seens like its doing