ellery crossman

I recently replaced clutch, throw out and pressure plate on my 97 F150 4x4. It worked great for 3 days. As i was crusing down the hey at 70mph, it suddenly started coasting. there was no grab from the clutch, still had pedal but no clutch avtion. after pulling over, i had a friend depress the clutch pedal and i could feel the throw out bearing moving but the truck will not move. Any ideas before I tear it apart?