I bought a 2006 Ranger(4x4) in November of 05' and after a few months the underbody is rusting badly.. have yet to take it 4x4ing. I did lots of research on rustproofing and 90% of feedback said not to get it, it's not necessary. Is this problem fixable in the early stages.. or is the damage done already?? Are you guys rustrproofing your trucks??