'89 635csi tranny part question

My mechanic says that the "electronic component" of my transmission is bad and needs to be replaced and quoted me about $1,200 parts/labor for it to be fixed. He says it's not the entire thing. I need to call him and get this clarified, but he's gone for the day.

Is there a better term for this part that you guys know of?

http://www.bimmerfest.com/forums/forumdisplay.php?f=152