My 2010 silverado frame rot

[2010LTZ4x4]

Put it up on the lift today to change oil, looking around the underside and notice something odd looking along the gas tank. Poked around with a screwdriver and poked a hole right through it.  6in long on the inside along the bottom. Looks like I'll be buying a frame section and welding it in.  Safe-t-cap sells all different  frame sections. 

Not impressed, even after all the under coating I've put on all these years 14 to be exact. This sucks.   

[richard wysong]

Do a close inspection up front, the frames rust from the inside out so it may look ok but have no strength