7.3 with 6speed clutch, or tranny bad?

[thestartupman]

Need help, I have a 2000 F450 with 7.3, and 6 speed manual tranny. I was driving to town, and noticed it was a little hard going into gear, and I could feel a little vibrashin coming through the clutch pedal. Now, I had it towed home, and If I put it in low gear or Reverse, it will go in hard and seems to bite, but if you apply throttle, it slips and makes a grinding noise. All other gears will go in but all of them make the grinding noise, and it just slips. Is this a clutch problem, or the trany? By the way, no fluids leaking on the truck.