1995 Ford Explorer Many problems all at one time.

Ok last night my truck started fine but when I put it into drive it made a loud ticking sound then when I put it back into park it made a loud grinding noise. It would not go at all when put in drive and also wouldnt stay in park (it rolled). We had to use the emergency brake. The wheels and steering column then locked up as well. Now I just bought this truck from an individual recently and I noticed right away that it was slipping so I thought maybe it just needed a trannsmission filter but then all of this happened.