Porter King Winkler in Dieppe, France

I am looking for any info on my grandfather, Porter King Winkler.All I know is that he was in the Army during WWII and the only picture I have is of him standing on a "BIG" truck, looks like a wrecker, and on the side " BIG PETER "is printed.It says on the back Dieppe, France 1944.This is all I have and I hope someone out there might have known him or maybe know what the truck was and what kind of job he would have had if he was driving this truck.I have to have more info to send for his records.Thank You very much!