Made loud pop an then grinding noise .. now just grinds an won't go.4x4 or 2hi on 2006 Chevrolet Silverado 2500 HD

Made loud pop an then grinding noise when started to pull in 4lo reverse.. now when start truck it makes grinding noise in P. R.N ... stoos n drive.. but wont go at all... sounded like popped out if gear when happened but now just grinds n 4hi.low an 2hi... had no trouble at all before

Will the PARK position still hold the truck from rolling?
Yes. If lift all four tires off the ground I can spin them but the drive line don't turn... if I turn the drive lines the wheels barely turn