I'm having some preventative rust repair work done to my 93 D350 (72,000 miles). Truck overall is in mint rust free condition however, when the body shop removed the windshield to redo the cab roof and hood, they found that the rubber winshield gasket was hiding some rust holes just under the front rain gutter. I attribute this to the Lund sun visor that the original owner had installed on the truck attibuting to possible leakage. Area has been treated with POR 15 on the inside and with a rust "converter" treatment on the exposed exterior area.
I removed the sin visor and am having the holes welded over. With two daughters in college I didn't have the money to have the entire truck painted. Maybe in another couple of years

John

 

That's the first I've heard of rust there. Usually they rust above the gutter from the inside out.

Michael, are you reading this?

 

I know all bout the rust there at least you caught yours in time

 

My 78 Club Cab has the sme problem, below the drip rail. Most of the 70's era dodge seem to be like this.