There is noooo way you can use a socket on the torque converter drain plug. Just no room. Maybe an inch from the drain plug to the crossover pipe. A regular allen wrench won't work either. Had to cut the short end off of one to get it to fit. Getting it back is even worse since you can only turn the wrench 60 degrees at a time. Had to use a magnet and a paperclip to get it started. Maybe this is just my car but have you done this on an E420?