Browsed a little bit, didn't see it in the first couple of pages so sorry if it's been covered. I bought an upgrade receiver hitch (because I have zero faith in the factory junk) I did the same with my 02 2500hd and it was a five minute job, but I can't figure this out. It's an 04 2500 Av. I removed all the bolts but two on the passenger side, for some stupid reason they didn't use captured bolts on all of them like my hd pickup, and there are two I can't get at to hold a wrench or socket on the bits. There is a black plastic box in the way. I'm guessing it has to do with evap system. So I removed the small bolt at the bottom, but there's another one mounted upside down at the top that's inaccessible. Anyone know how to get this stupid thing out of the way so I can get the last two bolts?