Correct - that hole goes through and so could chips. I remember my dad had the same problem one time and greased up a left hand drill and "luckily" got the bolt to spin out on its own before going all the way into the transmission cavity. The chips he did have stuck to the grease. He seemed to be lucky using his left hand drill method on several other bolts as I recall. Im sure if it was me, it wouldnt have been the case. If your going to drill it - you may want to try it.