http://www.continentalimports.com/ser_ic20242.html AUTOMATIC TRANSMISSION ADJUSTMENT ARTICLE
WIKI Transmission adjustment
http://www.peachparts.com/Wikka/TransVacTune
Transmission adjustment Thread
http://www.peachparts.com/shopforum/showthread.php?t=158216
If you were going to get a rebuilt trans they would just exchange it. In that case you might as well see if you can improve it or just drive it until it stops and get the exchange or a used one.
Also abnormal; at least on american cars to find particals in the Pan during a filter change. It is from the Bands and clutches and even on a new trans they wear and the particles have to end up somewhere.
I have read the Mechanics will often show what is in the pan to scare folks into replacing their transmission.