I believe the space behind the red grille is usually left open when the chassis is originally constructed by Perterbilt. I think the intent is to provide space for a front engine PTO (FEPTO). In this case, I think the grille (and skid plate below) were installed by spec. to protect the intercooler which I believe is mounted below the radiator. The cab pivot points are also behind the grille. I'm happy to be corrected by those who might be more in the know.What's the purpose of the red section at the bottom of the grill? The only purpose I could possibly think of would be extra protection but if that's the only purpose they certainly could have done it in chrome or stainless steel to make it look much better of course also not having the diamond plate on the roof would also make them look better!