T56 problems- clutch or trans?

Not real knowledgeable on the manual transmissions. Needing some thoughts on what the issue is here.

At the track yesterday with my 5.7 hemi/T56 Warlock. On my shift into 2nd I heard a noise and the motor started revving. Limped it down track with what I thought was badly slipping clutch. Got to the pits to check things over. It barely moves before acting like it slips and makes all sorts of growly, snapping, popping noises. No noise in neutral, coasts just fine. Clutch in, no noise. Clutch out, sickening noise. Out of curiosity, we pushed the car by hand in gear to see if it would move and it did with some noise.

My first thought was the clutch is gone as it moves (slips)in gear. But I dont know enough about these to know is - that if the clutch were still good but the gear set is toast (or something else) if it would move with clutch engaged- like is happening.

Just trying to figure out if the trans is toast or the clutch.

TIA
Are you using a hydraulic release bearing?
If clutch was slipping, I think you'd smell it!
I'd bet it's trans. drain oil and inspect for debris.
Hope I'm wrong!