i traded a 6.0 for a 6.2 the biggest difference is the operating rpms i pull an 8000lb travel trailer and a cattle trailer at about 10000lb loaded the 6.0 probably pulled a little better but not much.i dont think you will have any trouble pulling that load you should probably get the 4.30gears tho i have the 3.73s and they do fine pullin what i do but the 4.30s wud proly be best for that amount of weight.

ok thanks, I wont be pulling the load very often just on the weekends during the summer the longest tractor pull is 1oo miles away so i would maybe put on 1000 miles a year pulling that amount of weight. The rest will be just driving back and forth to my farm and other errands. I will only put on about 10-15K miles on a year i hope. Now i talked to a man from the dealership and he said that total weight of a trailer you could pull was 15,000 lbs now if my trailer is 18,500 lbs am i gonna break something? Now if i get the 3.73 gears will i heat my rearend pretty quick or what kind of mileage will i get with the 4.30? are those the only 2 options they come in?

Sadly, most dealership sales people have no idea what a trailer is, or how to attach one. You may notice that most of them don't drive pickups either. You can't liscense the truck to pull more than 15,000 legally, but it won't break it. However, if you are dragging around that much weight you probably should be looking at a 2-ton truck to pull it.

im using a triple axle trailer with 7K lb axles. what do you mean by a 2 ton truck?

You should look into a 450 or 550. They are rated heavier, but have to be liscensed commercial.

I have no doubt it'll pull 18,5k lbs, but there's a point in which safety (you and everyone else on the road) comes into play and I think you hit that point. At 18,5k lbs, you'd probably be over on the tire/wheel ratings, which realistically is your "weakest" point.

How about a dually? I just checked the towing specs on the gas dually, they aren't much better than the SRW. You'll really gain GCWR when you bump up to the diesel.

Gas dually 4.30s - GCWR = 22,500lbs
Diesel dually 3.73's - GCWR = 30,000lbs

My truck came in right around 8,000lbs on the scales...

On a gooseneck though most of that weight will be on the trailer. I hope that i can get the weight centered mainly on the triple 7Klb axles to lighten up the load on the rear axle of the truck.