engine revved like i was in neutral?

i was driving for about 30 minutes and just pulled away from a stop sign. the truck did not make any weird noises but seemed to be shifting into the next gear when the engine revved like i was in neutral. tried every gear even in 4 wd and had nothing. had towed home on flatbed, not cheap. the seem to lock in park but in any drive or reverse the wheels roll freely. is this a catastrophic failure of the trans.? no unusual noises were heard at time of problem.