740i Trans lock

I had a problem with my 740 locking in one gear. I found that a piece of card board had got caught in the Aux fan, which burned the motor out.. After three tries to get a used one that worked, i finally sellted on a new oine. I asked your people how to check out all the electrcal parts that control the fan. I got an answere, that gave me great detail on how that is done. He was exactly right,and now that the Aux fan is fixed I have no more trans. problems. I have lost the information, and dont know who sent me the info. I do want to thank that individul, and Bimmerfest. What a great site.