I'd like to know what gears your truck had previously (if any) and how you think the truck drives now specifically towing.

Thanks

 

I may have some info for you. I previously had the "Fuel Efficient" 3.31:1 gears in my truck-2002 ext cab/4.6/ 4x4 I now have 4.10:1 gears in my truck and have had 265/70-16 tires on mine while towing. I pulled a 7'x14' v nose trailer cross country ( Florida-Washington state) Trailer weight
7000 lbs. Pulled great. I have also pulled a 8.5'x 18' trailer (7000 lbs +) on the same route, but with a much smaller tire- using 235/70-16.
Towing is not a problem for me and what I do with my truck and have hauled trailers around for friends. A good weight distributing hitch will also help, and an electronic brake controller if your trailer has electric brakes. If your trailer has electric brakes, I strongly suggest adjusting the brakes to achieve maximum breaking from the trailer. Adjust the load in the trailer as to not have too much tongue weight. If you haven't already, get a good transmission cooler installed. This will greatly help in preserving your transmission. I Also suggest a two core radiator if you already do not have one.
Visit your owner manual and towing section, to get a glimpse of what your towing limits are for your wheel size/axle ratio.
Also, there is a towing forum which may give you some more insight into what you are trying for in your particular setup.
I hope this post helps you out, feel free to ask questions! Cheers!

 

That is an impressive amount of weight for a 4.6. What is your fuel economy like with bigger tires loaded and unloaded? Can you tow in overdrive now? What was mileage like before gear change unloaded?
Pulling a 7k lbs boat with 4 adults in the cab on relatively flat ground running 65-70 netted me a God-awful 6.5 mpg! The truck labors some thanks to the weight and a lot of wind resistance (boat is 10' at the windshield). I have yet to get better than 15mpg, but I have never ran unloaded on the highway long enough to see what the old beast is capable of. I can't help but wonder if 4:10 would help all around, but I'm afraid my mpg at 70 running 2700 rpms unloaded will get worse.
The other issue is coughing up $2k in gears for a truck that is worth $10k at best (it is mint btw ) knowing in another 5 years my kids will be too big for the back seats. Decisions, decisions!
I currently have 3:55's with the factory tow package. If memory serves me right, the unmodified version of my truck with a 5.4 was good for about 6,800 lbs.

 

I now have 285/75-17 Nitto Terra Grappler tires on the truck. I have not towed in a while, but the fuel economy unloaded is averaging 13 in the city and an impressive 15.5-17 with highway driving. I remember the mileage with the 265/70-16 tires being around 14 mpg average unloaded. When towing with that setup, and the 7000lb trailer, the mpg were around 7-8 mpg. Highly suggest not towing in overdrive, but to each his own. Not sure of the mileage before the gear change, I did not own the truck too long before I changed the gears out. I specifically changed to the 4.10:1 with a 235/70-16 tire size combo to ensure I had enough "Umpfh" to pull the trailer I purchased.
I changed a few other things along with the 3.31:1 to a 4.10:1 gear change:
-Larger radiator(2 core), Transmission cooler( for vehicles up to 30,000 lbs), Shift kit installed in the transmission, Amsoil Synthetic gear lube in both front and rear diffs, Amsoil ATF in the transmission. Electric Brake controller, Heavy duty relays for towing installed in the power distribution box, 7 pin wiring harness. Later included was the Troyer dual 16" electric fans. I also added Hellwig load assist springs.

 

If I could get those numbers, I'd be very inclined to swap them out. I don't drive it in the winter, so might make a great project. Does that take into consideration speedo change for the tires and gears?
I have a heavy duty towing converter and was told I could tow in od as long as I was dropping in and out of od. Current issue is I'm not making enough torque at 2100 rpm to stay in od with my gears.
Troyer and another reputable tuner advised me that the tow package cooling system had ample reserve for what I was doing.
because I can easily adjust my tongue weight by moving the boat around, the truck is balanced nicely. A set of Bilstein ' s is likely the only addition I need.
Upgraded brakes to POWERSTOP extreme service. Worth every penny!

Thanks for the info.

 

I'm sure you are aware that going from 3.55s to 3.73s isn't going to change much and is not worth the expenditure. Even 4.10s is only a 15% change or increase in engine rpm. Lately, I've been thinking about going to 4.10s and instead of 265/70x17 stock tires, use 285/70x17 P tires because I like to drive on the beach. The tire change decreases engine rpm by 3%. But, like you say, it's a lot of expense for an old truck. A tune definitely helps in hp and economy. I have the superchips tune and I like the results.

 

With 7k lbs I usually run a 93 tune. I don't have any more tuning to do! I run the same tune unloaded. The tuner I have worked with claims there is little economy improvement with a 93 non towing tune. I tend to believe him considering the truck runs closed loop most of the time anyway.
Running 3200 rpm's towing concerns me with 4.10s making my fuel economy even worse. If I can tow in overdrive with the converter locked up at 2800, I would think I could see a nice improvement. The trade off being running in od unloaded turning 3100 at 70 ish. Looking at dyno runs with long tubes, I think the 5.4 breaths easier at a little higher rpm than stock possibly helping economy despite more revs.

 

Yes these are the correct numbers, as I also run a Diablo Tuner on it, to account for the gear change and tire change.