awd mode is 4 green lights on the dash no center light
4wd is all 4 green lights on dash and center red light lit
put in 2wd mode, neutral, jack stands in rear, raise rear end up both tires free
parking brake off
can you turn both rear wheels by hand ?
no, parking brake stuck ?
no, possible center diff issue ?
does turning one wheel, make the other move in the opposite direction ? yes OK
no, possible stuck rear locker ?