mijpa, call me sometime, it won't cost you anywhere near $1600 to get it motivated to pull your load. A box will make a huge difference.
3.73's will pull 12K just fine. My 03 when it was new would pull 14K with just an EZ without an issue. They do need a little help to keep speeds up on grades around here.
What hills were you getting passed on?
I'm just right down the 303 from you probably less than 10 miles.

 

My neighbors dually with 3.73s and mine with 4.10s pull entirely differant.He says mine pulls lots stronger.I towed 10k through the Smokey mountains a few weeks ago and all but the biggest grades no downshift from 6th.The big grades I downshifted not far from the top of them.65 mph up the hill and 65 mph down the hill.Most of the time with cruise on.His won't do that.

 

The 373 and the 410 rears sure have advantages to each other.

I chose the 373 for mileage cruising down the highway. I rode in a 410 truck towing and it was better...not a hug difference but better.
I looked at putting a 265/70/17 on my truck to lower the tire height a bit and PSUEDO change the gearing to ...about 400. I canned that idea and put some power to it.

Towing heavy is easy to get going. Stopping is just as important.

Looking at the overhead on a hill will show you the worst. I have seen 6, loaded to 33Klbs LOL Take an average hand calculated.

Scotty

 

Why do you say that?

And if that's true, why would anyone spend the extra bucks to get a box??

Not sure exactly what you mean.

 

I'm just right down the 303 from you probably less than 10 miles. I pm'd you can you give me a call. Struggled up sunset point/ crown king

 

Just want to thank everyone for their input. Fred Swanson thanks for the call and allowing me to pick your brain.

 

I have the 2005 610 and I used to have the 2003 HO with the 305/555......I can definatly feel the difference.....it is a hug one.....good luck

 

White Lightning, Great kick me when i'm down :}

After speaking with some of the seior members I feel much better. The problem was The way i was driving it. I put it in to tow/haul to late and the tranny wouldn't engage into the correct gear and wouldn't let me leave that gear to go into the correct gear to send full power. Feel pretty stupid but at least it's not my truck.

 

I just tell the information that is true......I can feel a huge difference....But i'm not saying that your truck is not a monster...Have fun

 

Don't let anyone talk you into buying something to increase your hp unless your willing to give up your warranty. The extra Hp sounds good at a moment like this but if you value your warranty even a little bit you will kick yourself in the *** later when you try to get something fixed under warranty. Been there done that.

Every one talks about super duper fuel mileage and pulling power that never ends. Well I have owned two Cummins diesels, one 1999 and one 2005 model, both bought new. The 05 pulls as good as the boxed and injected 99 but the fuel mileage is about the same. I have been on diesel web sites ever since 99. It doesn't matter if it's a Ford, Chevy, or Dodge everyone thinks theres is the best and gets better mileage than reality. I had a bet going on many sites at one time for anyone to come and prove to me that there truck can get 16 MPG pulling 3500 lbs at 65 MPH over a 200 miles course and I would pay for the fuel and give them a $100.00 after wards if it did. To this day no one has taken me up on the offer. Talk is cheap, well not if you start bombing and loose your warranty on a $40,000.00 truck.

Thanks for listening, I'll get down off the soap box now.