I’m assuming that what they found in the pan was a lot of clutch material. The clutches themselves consist of a bunch of different parts (see the clutch pack pic about 1/2 down the page ~ http://www.familycar.com/transmission.htm) and can’t really end up in the pan - though parts of them can.
In any case, as bloody_knuckles said the transmissions in those were very trouble prone. Yours will need to be rebuilt or replaced with a remanufactured unit and if you get back on the road for $2500 you’re doing well.