Our first TV was a 1987 3/4 ton Chevy with the old 350 and we towed an Eagle 215SD along with a 19' Bayliner Capri. Last trip we took with it we got 5.3 mpg towing both trailers. Traded for a 454 and then a Vortec, much better towing ability but mileage was pretty bad, 10 around town and 8 towing the outfits. Switched to a 2003 GMC Duramax and it was a world of difference, got around 14 in town and 12 towing the outfits from 2002 through 2011 with the same FW and four different boats, up to 5,000 pounds on one of the boats. Now tow a Eagle Superlite HT 26.5 RLS and a boat with a 2012 GMC 2500HD D/A combo crew cab and get around 12 and around 11.5 towing here in the mountains. As far as maintenance, oil changes take more oil, but with less frequency so it's about a wash, oil filters cost about the same, fuel filters are quite a bit more expensive, but haven't run into any bad diesel causing the fuel filter to fail early. Transmission and differential maintenance are about the same, I would guess. Where the more expensive costs come in, I believe, are the initial premium and the fact that diesel, when I bought the first one the diesel cost less than unleaded regular, is now over $.70 a gallon more than unleaded regular. As far as fuel costs, due to the increased mileage, it's probably almost a wash at that differential. When it drops back down to around $.30 or $.40 difference, than it's really more cost effective to drive the diesel, in my opinion. There is no comparison in the way a diesel tows and a gasser tows. However, if most of you driving will be without towing, a gasser will probably be a better option, until you get ready to go somewhere. I know I will probably not go back to a gasser, especially since the dealers no longer make a big block towing machine, they are now telling us through their manufacturing that a 6.0, 6.2 or a 5.7 is an adequate towing set-up. I am skeptical of that thought process.
