[soulman]

Good evening all,

I've been"lurking" for a while now....I read a gazillion posts.....done many searches and now have a question.
First, I have a 2005 Dodge 2500 QC 4x4 SB auto with 285/70-17's. I love my truck and bought it to pull our present camper and our next one, as well. I have no idea what the rear end is (3.73/4.10?) and don't know how to find out.
Having had the truck for just a month, I've only had 3 fill-ups at 3 different vendors.
I'm not too unhappy with the mileage but would like to improve it. I've gotten 19.7 (son fill-up so not sure), 15.1 and 18.77 today. Mostly combination of hwy/city.
My son (at UNOH studying to be a diesel mechanic) said I have an MBRP 4" exhaust and a k/n air filter. I've added an Edge Mileage Max and a block heater cord.
QUESTION: I've been thinking about putting on a tonneau cover. It seems the camp is divided on whether it helps mileage. Do I buy one or save my money?

Thanks,
John