Just bought a 06 duramax and the whole body is mint and hardly any rust on the frame but the box supports are rotted in the middle and my friend just bought a 06 too and same thing as mine.Whats the deal with this it seems to be really common my friend looked at a 07 classic dually where he bought his and the supports were almost completely gone too..Did they use different metal or something my 01 had rust on the rockers but the supports were mint..Kinda sucks being I now have to replace these..