Went past a Ford dealer couple weeks ago and noticed he had 2 SD dallies on the lot. Stopped by the following week to take a gander at them. 1 was a 450 Lariat and the other a 350 XLT. 79 and 70K respectively. Anyways, didn't spend a whole lotta time there, but on the 350 (very well equipped), it was a '21, 4.10 gears and had the 10 speed tranny. So it got me to thinking and perhaps a little drooling too, but what is the RPM difference between a 4.10 6 speed and 4.10 10 speed at 60-70 mph? On my '17 350 w/ the 4.10 6 spd, I'm at 2100 at 70 mph.

10th gear in the 10R140 is .632:1 and 6th gear in the 6R140 is .674:1. That is a 126 rpm difference at 70 with 32 inch tires putting the 10R140 at 1,905 rpm and the 6R140 at 2031 rpm in their final gear. I am not sure what the size the F350/450 tires are so that is just guess.

Good info Shiner, tire size guess, no problem!Jerry

I'm curious too. What is a dallie?

IDman wrote:I'm curious too. What is a dallie?I think he meant Duallie

IDman wrote:I'm curious too. What is a dallie?I suspect an auto spell corrected DUALIE.

Curiosity caught the Cheshire cat | Good Sam Community

kellem
Explorer
Dec 12, 2020
Interesting, have not heard of anyone complain about their towing experience with the 7.3 regardless of gear ratio but a consistent report of better fuel economy with 3.55 empty....1 mpg still counts.

Note:
I'm towing a 30ft 7500# trailer loaded so from my perspective, like towing a p'up.
Cummins12V98
Explorer III
Dec 12, 2020
deltabravo wrote:
Cummins12V98 wrote:
Also wondering what a “DULLY” is???

A DULLY is a non "shiny" truck

;)

Thanks!!!!
deltabravo
Nomad
Dec 11, 2020
Cummins12V98 wrote:
Also wondering what a “DULLY” is???

A DULLY is a non "shiny" truck

;)
Crespro
Explorer
Dec 11, 2020
ACZL wrote:
Went past a Ford dealer couple weeks ago and noticed he had 2 SD dallies on the lot. Stopped by the following week to take a gander at them. 1 was a 450 Lariat and the other a 350 XLT. 79 and 70K respectively. Anyways, didn't spend a whole lotta time there, but on the 350 (very well equipped), it was a '21, 4.10 gears and had the 10 speed tranny. So it got me to thinking and perhaps a little drooling too, but what is the RPM difference between a 4.10 6 speed and 4.10 10 speed at 60-70 mph? On my '17 350 w/ the 4.10 6 spd, I'm at 2100 at 70 mph.

With my 7.3L, ten speed and 4.30, I run just under 2,000 rpm at 65 mph. I think the 4.30 and 7.3 is an excellent combination.
ACZL
Explorer
Dec 11, 2020
bucky wrote:
I think in the op's case it would be drooly.

Hey now!! LOL Never hurts to look. Reminds me of a saying from a former semi driver (RIP) who said while dining out with his wife and a good looking lady walks by: "Just because I'm on a diet doesn't meant I cannot look at the menu".
Grit_dog
Navigator
Dec 11, 2020
kellem wrote:
Word on the street is Fords new 10spd is allowing truck buyers to tow happily with 3.55 gears instead of 4.30.....tight gear spacing.

I fell victim to the 10spd and 7.3, ouch.

Ouch?
I say yay!
If one is dropping tht kind of $ on a new truck, using it to tow, has the luxury of a 10 speed with deep OD gears, why would you not choose the best performing, most capable package for basically free?

I would hazard a bet that the fuel economy penalty is miniscule at most and non existent in some conditions (like when towing).
bucky
Explorer II
Dec 11, 2020
I think in the op's case it would be drooly.
dodge_guy
Explorer II
Dec 11, 2020
Even with the 10 speed trans, deeper gearing is always best for a gasser. Unless you are towing light, get the 4.30's. Performance will be better and mileage will be about the same!
Grit_dog
Navigator
Dec 10, 2020
Hannibal wrote:
kellem wrote:
Word on the street is Fords new 10spd is allowing truck buyers to tow happily with 3.55 gears instead of 4.30.....tight gear spacing.

I fell victim to the 10spd and 7.3, ouch.

Me too. Love the new truck with 7.3L, 10spd, 3.55.

Which is a yuuuuge step up from your old truck, but I suspect kellem was talking tongue in cheek, because the deep gears behind the 7.3 make it a monster and with the 10 speed and rpms for days it can run 4.30s no problem and still have low rpms running bobtail.
rhagfo
Explorer III
Dec 10, 2020
Hannibal wrote:
kellem wrote:
Word on the street is Fords new 10spd is allowing truck buyers to tow happily with 3.55 gears instead of 4.30.....tight gear spacing.

I fell victim to the 10spd and 7.3, ouch.

Me too. Love the new truck with 7.3L, 10spd, 3.55.

This is a lot of it, the 10 speed allows for lower ratios in the lower gears to get moving. So the transmission is making up for the rear end.