My car seemed to leave fine, when i shifted to 2nd got a load bang and that was it. No fwd gears, reverse works, fluid changes levels between park and N, sprag seems to be fine, there were no parts in the pan. Fluid gets changed and bands checked every 20-30 runs.

How much line pressure ? ...

mine did the same 2 week's ago but no bang. prob. the platery gear? bradp.s i did find alum. in the pan but have not taken it apart yet.

PROB blew-out one of the rubber seals in the rear clutch pack.

No FWD gears and reverse working is typically a symptom of the rear clutch (forward gear clutch) not working. But it might be something else. The bottom line from your view in the pan, it will require the trans to come out to fix it. Then it might be more obvious what happened.

The loud noise makes me wonder if it is something else.

Let us know.