Hi:
So i have a 2017 6.7 Diesel DRW with 4.10 gears. The truck is amazing compared to my 2005 SRW.

I mostly pull a gooseneck trailer about 12,000 LBS getting 9 MPG. So i take a trip to get two Hondas UTV'S. Pulled a small utility trailer 7 X 10 trailer not very heavy. On the way there I was getting 11 MPG. I was shocked at how bad it was. On the way home I got 9 MPG. One in the bed of the truck and other on trailer. So there is some wind resistance there but no were the weight of the gooseneck trailer.

Both ways when the speed limit was 70 MPH I drove at 77 MPH. It must be the speed that is killing the milage not the weight.

The guys running DRW trucks any of you getting better mileage with the 3.73 or the 3.55 gears?

Any one have a 2020 10 speed trans with 6.7 DRW? If so what are the results in mileage?

Is it worth putting in 3.55 gears? Than is it a forscan to change computer to the diffrent gears? Or is there more to it than that?

Thank you

 

I get mid 12s in my 18 F450 running 75MPH unloaded.

 

18 350 DRW 3.55s here.

In stock form I got 7mpg towing my 42ft 13,000lb loaded 5er RV @ 70mph.

Deleted and now get 9.5mpg towing the same trailer at 70mph

I get 18+ unloaded at 70mph. Ive gotten as high as 20+ at 70mph a few times on flat terrain.



Some details left out of your equation tho. Whats the altitude in the places of travel? Same 2 trucks but one in the mountains will have a big difference in fuel mileage vs one down south on flat terrain & low altitude.

Aero drag is the biggest issue for hurting fuel mileage. And the faster the truck is traveling, the higher the aero drag so more fuel will be used.

I get 25+mpg at 55-60mph & it drops from there the faster the truck is traveling.

I feel like these truck are way over-geared IMO.
A 2020 with 3.55s & 10 speed should be very capable and not make any significant difference in towing vs 4.10s with a 6 speed.

 

You could also put taller tires on and reduce the final drive ratio & forscan to correct the speedo at a much lower cost then new gears. But the taller tires will raise the truck possibly negating any mpg increase.

 

I live in Wisconsin and the trop was Mississippi. So elevation is around 900 feet I believe no mountains pretty flat this trip.
I found a calculator hear are the results.

My truck 6 speed 6th gear is .69:1 with the 4.10 gears with 31.5 tall tires at 77 MPH = 2324 RPM
If I had 3.73 = 2114 RPM
If I had 3.55 = 2012 RPM

Off Ford Website the Ten speed tenth gear would be .632:1
Same numbers used with .632 gears would be.

4.10 = 2128 RPM
3.73 = 1936 RPM
3.55 = 1843 RPM

Wow what a difference in RPM from the 6 speed trans to the 10 speed. These engines are torque monsters at 1050 LBS. So I don't think you need to spin them so fast at 77 MPH and still get the job done.

So the question is , is it really worth the upgrade to a 2020 truck with 10 speed or re-gear my 2017?

 

So the delete really helps the mileage I wonder what the results are from most people. Would have to wait till warranty ended. Before I would do that.

 

New gears will be cheaper then a trade in loss and more cost for the 2020.

2020 6,7L option is now $10,500 vs the $9,000 from 17-19. Plus the base price of the truck is higher. Your same truck in 2020 version will be $6,000-$7,000 higher MSRP. then factor sales tax and trade in loss/difference.

New Gears are the correct way financially speaking. Or driving slower, haha.

But u will get more HP & TQ too.

 

Just remember, if you have 4WD both front and rear gear sets will have to be changed.

If you have a 2WD then its a no-brainer to gear it.

As far as the electronics side, I dont know if Forscan will work for changing gear ratios. A Ford service center can probably change the computer for gears. Problem is getting the truck there. Dont know if it can be driven before the computer is changed for gear ratio change. ?

 

Never thought of that one daaaaaaaa. change front gears also! $$$$$$

I don't want to slow down takes for ever going so far that way!

 

My 2020 F350 platinum with 3.55 is hovering around 18-19 mpg with our driving. Pulled our steel deck 28’ GN car hauler and averaged 15 for 370 miles. Trailer wasn’t loaded heavy or catching much wind. This is doing excellent on fuel. 700 miles total on it so far

brett

 

Wow I am happy for you the ten speed is doing you right!

 

Wind drag is a thing... big thing. more so than weight. I used to have a 8x12' enclosed trailer. I would get 11 towing it. Wind drag will stop your fuel a lot more than weight usually. For instance, I can tow my dump trailer loaded down to around 17k and get 14 mpg. Gooseneck horse trailer weighing 14-15k and its more like 9-11mpg... Sometimes 7-8 if in a head wind or up hills etc.

 

Is it a dually?

 

I was going to try a ram this go around until ford announced their numbers and the 10 speed. It became a no brainer to get a ford. At 70, it’s around 1500 rpms. I also run in eco mode and drive for mileage. When I need power though it’s impressive

Yes. Installing a Carli lift and 285s though. Lift next week, tires tomorrow

brett

 

Thats awesome numbers! 15-16 empty seems to be the best I can squeek out. Hoping when summer fuel is out I get a bit more.