I won't go into all the trucks I have owned in the past, but the last truck I had before my current truck was an "02" Silverado with a 6.0 Gas engine, 4x4 EC, SB. Bought it new and it did a great job towing my 26' enclosed car trailer when I was drag racing. It did good when we towed our 20' Dutchmen Cub ultra light. It was when we bought the KZ MXT 264R toy hauler she started running into some problems. Granted she had 157.000 miles on her clock, but it was time for her to find another home. I didn't want to chance having her break down with my coach, DW, my Harley and 6 dogs along for the ride.
Current truck is a "08" Silverado LMM Duramax/Allison 4x4, EC, SB. originally a 2500HD, but now a 3500HD. The difference in towing is night and day. The initial fuel mileage was also much better. 17.6 vs 12mpg not towing. However both trucks got around the same mileage towing (around 9 mpg) that is until I had some modifications done to the diesel which took it from 8.6 mpg to between 11 and 13 mpg towing a Voltage 3200 Epic which weighs around 15,000 lbs., but has a GVW of 16,500 but we never load it that heavy due to our truck being SRW. Granted you'll have an extra filter on the Diesel (external trans filter) that you didn't have on the Gasser that you will need to change. The cost to replace all the filters on a diesel will be around $160 if you use wix or another premium filter plus 10.5 quarts of oil VS 6 quarts for the gasser. In the end the cost works out to be fairly equal because of the better mileage and you will not have to change the fuel or the external trans filter very often as well.
My rule was if you are towing 10,000lbs or more you need a Diesel if not then stay with a gasser. Personally I would never go back to a gasser. The power and torque you get from a Diesel is no less than amazing. The maintenance will be slightly more expensive, but what you get in return is worth the price. Diesels are a little more picky when it comes to cold weather starts and much more expensive if you have to have any major work done to them, but if taken care of a diesel will outlast a gasser three times over. IMO the maintenance costs were not out of line as far as expense goes even though my diesel is more expensive to maintain because I use nothing but Wix filters and Schaefer oils, but to me piece of mind is worth something and I get piece of mind by doing all of my own maintenance and using premium grade filters and lubricants.
