I just got a 2012 RAV4 with 150000 miles on it. I've decoded to service the transmission. I have never done one before but, it looks simple enough. However, before I started. I noticed that one of the transmission pan bolts has a nut in between the bolt and the pan as if it's being used as a spacer. Obviously whoever serviced it last put it there. My question is why? Now I'm worried something is gonna be wrong with the bolt thread and I'm not gonna be able to put the bolt back in and I have no way of fixing it.