Power uphill towing.
 

Maybe there’s something wrong with yours. My 07 E350 v10 towed my enclosed 20’ trailer very well. 6500+ pounds for round trips between 150-200 miles 10-12 times per year.
Mostly relatively flat highways but even that has some downshifts.

Or maybe yours is doing just fine but you’re thrown off by the different powerband.

Oh hey this just hit me:
my trailer empty is 3500lbs (same as yours loaded), and man it felt like nothing back there. She zipped around like it did with no load.
Maybe something is wrong with yours.

V10 uphill tow.
 

Yeah, kind of weird, no codes, not cutting out etc. Temp stays good, but just wondering about catalytic converter or muffler? Also, maybe new plugs and coils/wires? Kinda stummped

What was the total effective gear ratio - tires & gears of the 2500 Chevy vs the F-350?

Definitely something wrong, My 07 with 4.10 gears ,one size bigger tires and 207,000 miles would hardly know it was towing anything at 3500lb. Pulls my 10,000+ camper way better than that. And yes, I do pull plenty of grades for i live in Idaho. As someone else mentioned maybe a plugged cat converter.

Is it just the rpm you’re concerned with? That’s the only specific ‘complaint’ you mentioned.

Because 4,000 rpm on a grade isn’t bad. I don’t have enough hills around central Florida to make a good judgment. The v10 is happy at higher rpm than other engines.

My question is how effectively does it accelerate under that load, on or off the grade, at that rpm ?
And how effectively does it hold speed ?

Also I forgot to mention mine has 3.73 gears, and with 3500lbs it feels like nothing. Literally feels like nothing on the gas pedal (brakes feel it a little bit at that load, but not bad).

I like the RPM question :-X22

Have you cleaned the MAF? (although that's probably not the problem, it's worth starting fresh).

You description makes me wonder if the variable-plenum intake is the problem. Maybe the actuator is not functioning? I think it's vacuum operated.

More info
 

The 2500 Chev also had 4.10, and similar model setup. Rpm's don't bother at 4k, but not really gaining any pull at that rpm. Know the V10 kicks in above 3k. Plenum actuator? Way to check/test? Besides that, I am assuming something isn't performing correctly. Just bugging crap out of me as purchased for the sake of camping, etc.

In the following picture, the actuator is the thing on the intake right behind the alternator. Did you check for any pending codes?


https://cimg7.ibsrv.net/gimg/www.for...4543e245df.jpg

No check engine light.
 

Not having any cel or codes know of. Guess can run a scan.

I would recommend pulling your plugs and take a good look at them.

I use my 2009 F350 V10 w/ 4.10 gears to carry a 2018 Wolf Creek 840 truck camper and behind that is our 2013 RZR XP 900-4 on a flat trailer. I can accelerate to 65+ if I go 4k RPM up a 10% grade, so something sounds a little off with that truck.

I like the responses stating your truck does that plus more easily. I know mine should too, but trying to figure out why it does not. Going to check plugs shortly, and possibly cats? Just weird, as runs good not under loaf, etc. and no check engine/service light. I am going to check fuel pressure also.

If the CATs are partially clogged it might be hard to find.
Our Exped 5.4L had a period of rain induced misfires, most of the time it would run fine, took awhile to pinpoint the leak.
Then I noticed the maximum speed it would climb a steep grade near our house was 65 mph, it used to take it easily at 75.
A couple of months later it would only go up the grade at 60 mph, then a few weeks later only 55.
Finally it wouldn't accelerate fast up to 65, but would get up to 65 slowly.
At idle it would rev fine.
One of the CATs was clogged.
I found a test online that used a vacuum gauge to show a clogged exhaust was the problem.
The CATs did not rattle inside when pounded which would indicate a broken honeycomb, I've had a couple like that.
This time it was probably melted or clogged.
New CATs and its' been fine for the last 5 years.
There's a test gauge available these days ($20 ebay) that uses a low pressure gauge with adapters to plug into an O2 port to measure exhaust pressure.