Had a slight chattering noise in the front of the engine, and clutches felt like they were slipping.

Pulled the engine and pulled front cover. The clutch drum is black, the weights look "burnt?" But the drum measured out ok. The one way bearing operated smoothly and felt like it held properly. But I had a noise after shutting down like something was still spinning inside.

Next question on the clutch discs. I dropped em so they got mixed up. Service manual says there are "A" and "B"? How can I tell em apart? I know the difference in the plates and discs but not the a and b.??