hi had the truck in the garage today changeing the front rotor and tie rod and happened to have it in 4lo while i was putting the wheel bearing back together i spun the wheel and noticed the front drive shaft turn accompanied with a grinding noise from the transfer case truck was in park and front drive shaft shouldn't have turned? is this a big problem or could it be shift rod adjustment issue thanks for any help or ideas

crawled under the truck this mornin to take a look and found the front driveshaft had striped the spline in the slip yoke