Harry-- Quite a bit of the time I see a piece of "stuff" that gets pulled
thru the gear sets or ring/pinion and suddenly there is a bunch of damage
done till the pieces are ground up.  The magnetic plug should have had a ball
of drek(scandahoovian for crap) on it if thats the case. The DU code trans
has the better ring/pin set, so thats the one to rebuild. The ACW  or ABD has
the 6 tooth crummy one installed. Ck web page at  aatransaxle.com  for  $$
details.
Good luck, Daryl of AA Transaxle