i took it back and showed them. it seems like the guy who worked on it did put a bung in the back of the cat but the threads where all messed up. so they decided to flip the cat over and put one in the front on the side of the cat. the shop tried to fix the messed up threads but couldn't so they just called me and said that they are putting a new bung in the back. no charge. thanks for all the info guys it helped a lot