First, suggest you read page 346 of the manual Ron posted (GREAT that
you can find this stuff).
Here it is:

Take note of the upper right paragraph and it means that they used
the base model, curb model, which is the stripper model with NOTHING
other than the towing option, a 150lb driver, fluids (depends too
as some only use half a tank, etc) and the hitch.
NOTHING
else and as it says, every thing else loaded
onto/into the TV will subtract, pound for pound, from the MTWR (they
call it TWR, which is more correct).
genekiwi wrote:
Okay, I get the point. More power more towing. AND I want to say thanks for ALL of the input.
Numbers I got:
Trailer towing weight: 9600
So, unless you have that 'curb' (aka stripper) model, this does NOT
apply to your TV. It will be less by the stuff loaded into/onto the TV
trailer dry weight 5695, max weight 8600 I took 7000 as a mid range weight.
That 'dry' is the curb or stripper model. It will weigh more after
the propane (some times even the empty bottles are not included), etc
are added
Assume that 8.6K is the trailer GVWR
I think the combined max weight is 15000.
Hitch weight is 572
Payload weight is about 1700
Again, this is based on the curb vehicle. Some OEMs are getting better
and have that yellow label, which uses the shipping weight vs GVWR
I don't have the truck to get definite numbers off of.
I liked the truck because it has a built in sway control and engine braking downhill. Better gas mileage is also a plus over the 2500 since not all of my driving is done towing.
I have owned the 2500HD for 6 years and time to retire it.
Hope you understand that you are going from a +9K GVWR down to a +7K GVWR
truck. Huge difference.
Besides, at my stage of maturity, this may well be my last truck that I will buy. ;)
Seriously, I know what you are talking about. I had an 02 1500 with the 4.8 and 4 speed. I towed a Jayco Kiwi 23B and yes, it was slow on the hills and I hit 35 mph at the top of one pass.
The Heartland I own is not quite 11 feet and has the rounded or slopped front which I hope will help. The Jayco I had was 11 plus and a flat front.
Neither the dw or I tow faster than 65 and usually in the 60 range.
Besides, I am retired and not in any hurry.
Again, your comments were and are appreciated.
Don't know what trailer other than your 8.6K GVWR. Most will weigh
much more than their listed 'dry' weight and depending on how you
load, many find that they end up very close to their trailer GVWR
A 3.42 diff is not a good choice for towing heavy (for the vehicle
class and you have gone down to the lowest class full sized pickup)
Worse if you put on over sized tires. The ratio from the OEM tire
dia to whatever you end up with will the the same ratio applied to
the diff ratio (reduction in towing capacity)
With the 5.3L and the 3.42, definitely going to be slow on the flats
and even slower on inclines and altitude.