4.10 rear in new Ford F350

[dennych1]

A lot of leftovers have the 4.10 rear any one know if there would be a big difference in MPG towing or would it be negligible..?

[Me_Again]

Lynnmor wrote:

Me Again wrote:
. What you think you gain with the lower diff gears in negated by the steeper OD ratio. Think final gear ratio!

Keep in mind that the transmission is worked harder with higher diff gears.

You multiply the top gear ratio times the diff gear ratio, and the result is always more torque with the lower rear gears. Add to that, each gear change is less of a difference in road speed, keeping the engine at a better RPM.

That basically applies in first gear to get a load moving.

Out on highway one is in 5th and the other in 6th at the same speed. You are dismissing a taller 6th gear od ratio. That is why I say the final gear ratio of the 4.10 truck in 6th is similar to the 3.42 in 5th. Both have enough lower gears. The Aisin has a deeper 1st and 2nd gear over the 68RFE. In the 4.10 truck the 1st gear is almost a waste, and some users would like to be able to lock it out. In the 3.42 truck you have a freeway cruiser in 6th, 80 MPH is only 1750 RPM and around 19 MPG.

I would have bought a 3.73 ratio if it was available, however at 60K on the clock and 4 years I am quite happy with 3.42 gears. We did two round trips from the NW to Arizona at 24,500 lbs combined and that combination worked well. We now commute back and forth with a TT at 16K combined.

I owned a truck with 4.10's and .69 OD for 14 years and a freeway cruise is was NOT. It towed fine however. It was gear bound with only 4 forward speeds.

[dodge_guy]

Me Again wrote:

Grit dog wrote:
And now we have the tall gears will out pull the low gears guys checking in.
Regardless of gas/diesel, number of trans gears, apples to apples, lower gears put more power to the ground.
I spose one could cherry pick one particular situation where the trans gears and torque curve of a particular vehicle might favor taller gears, but that will be a very select case.
Or all the mechanical engineers and theory are wrong......
Wonder why trucks with deeper gears generally are rated to tow more??

Back when trucks had 3 and 4 speed tranny's gear ratio really mattered. Now with 6-10 transmission we can look at final gear ratio based on the tranny gear in use.

Example the RAM with 3.42/Aisin in 5th has almost an identical final gear ratio was 4.10 truck in 6th gear.

The 4.10 truck in 6th is work against a .63 OD ratio while the 3.42 truck is in 5th working against a .77 OD ratio.

4.1 x 0.63=2.583
3.42 x 0.77=2.6334

Now add in the shorter tires on the dually with 4.10 and it is a wash. What you think you gain with the lower diff gears in negated by the steeper OD ratio. Think final gear ratio!

When the rear axle ratio changes it effectively changes each gear in the transmission. So with 4.10's each gear is more efficient. It's not just about cruising rpm, it's about efficiency.

[Lynnmor]

Me Again wrote:
. What you think you gain with the lower diff gears in negated by the steeper OD ratio. Think final gear ratio!

Keep in mind that the transmission is worked harder with higher diff gears.

You multiply the top gear ratio times the diff gear ratio, and the result is always more torque with the lower rear gears. Add to that, each gear change is less of a difference in road speed, keeping the engine at a better RPM.

[Me_Again]

Grit dog wrote:
And now we have the tall gears will out pull the low gears guys checking in.
Regardless of gas/diesel, number of trans gears, apples to apples, lower gears put more power to the ground.
I spose one could cherry pick one particular situation where the trans gears and torque curve of a particular vehicle might favor taller gears, but that will be a very select case.
Or all the mechanical engineers and theory are wrong......
Wonder why trucks with deeper gears generally are rated to tow more??

Back when trucks had 3 and 4 speed tranny's gear ratio really mattered. Now with 6-10 transmission we can look at final gear ratio based on the tranny gear in use.

Example the RAM with 3.42/Aisin in 5th has almost an identical final gear ratio was 4.10 truck in 6th gear.

The 4.10 truck in 6th is work against a .63 OD ratio while the 3.42 truck is in 5th working against a .77 OD ratio.

4.1 x 0.63=2.583
3.42 x 0.77=2.6334

Now add in the shorter tires on the dually with 4.10 and it is a wash. What you think you gain with the lower diff gears in negated by the steeper OD ratio. Think final gear ratio!

[dennych1]

Thanks for all this info while researching new truck

[Grit_dog]

And now we have the tall gears will out pull the low gears guys checking in.
Regardless of gas/diesel, number of trans gears, apples to apples, lower gears put more power to the ground.
I spose one could cherry pick one particular situation where the trans gears and torque curve of a particular vehicle might favor taller gears, but that will be a very select case.
Or all the mechanical engineers and theory are wrong......
Wonder why trucks with deeper gears generally are rated to tow more??

[Vanished]

We have a new '19 F350 diesel DRW w/ 4.10's - 15k trailer and 2k trip averaged about 11 mpg...

[dodge_guy]

Huntindog wrote:

4x4ord wrote:
The differeonce in 60mph high gear cruising rpm between 3.55 and 4.10 is 1524 rpm vs 1760 rpm. The power required to tow a 16k 5ver at 60 mph on level ground is only about 100 hp. The 6.7 can produce 320 hp at 1800 rpm. When peak hp is needed in the hills the 4.10 rear gears will have the transmission in 5th and the engine running 2260 rpm at 60 mph. The 3.55 gears would put the transmission in 4th gear with the engine running 2616 rpm. So the 3.55 gears are going to out pull the 4.10 gears on hills that the truck is capable of climbing at 60 mph. It takes a pretty steep hill or a very heavy trailer before the 4.10 gears offer the advantage.

Ummm. Fords max specs need the 4.10s. OP doesn't state what he will be towing. Just that he will have a 5500# camper, AND towing something occasionally.. He may be pushing that truck pretty hard.

Yep Exactly! The 4.10's are the way to go. It'll walk right past a similarly loaded 3.73 truck.

[Huntindog]

4x4ord wrote:
The differeonce in 60mph high gear cruising rpm between 3.55 and 4.10 is 1524 rpm vs 1760 rpm. The power required to tow a 16k 5ver at 60 mph on level ground is only about 100 hp. The 6.7 can produce 320 hp at 1800 rpm. When peak hp is needed in the hills the 4.10 rear gears will have the transmission in 5th and the engine running 2260 rpm at 60 mph. The 3.55 gears would put the transmission in 4th gear with the engine running 2616 rpm. So the 3.55 gears are going to out pull the 4.10 gears on hills that the truck is capable of climbing at 60 mph. It takes a pretty steep hill or a very heavy trailer before the 4.10 gears offer the advantage.

Ummm. Fords max specs need the 4.10s. OP doesn't state what he will be towing. Just that he will have a 5500# camper, AND towing something occasionally.. He may be pushing that truck pretty hard.

[4x4ord]

The differeonce in 60mph high gear cruising rpm between 3.55 and 4.10 is 1524 rpm vs 1760 rpm. The power required to tow a 16k 5ver at 60 mph on level ground is only about 100 hp. The 6.7 can produce 320 hp at 1800 rpm. When peak hp is needed in the hills the 4.10 rear gears will have the transmission in 5th and the engine running 2260 rpm at 60 mph. The 3.55 gears would put the transmission in 4th gear with the engine running 2616 rpm. So the 3.55 gears are going to out pull the 4.10 gears on hills that the truck is capable of climbing at 60 mph. It takes a pretty steep hill or a very heavy trailer before the 4.10 gears offer the advantage.

[spud1957]

Grit dog wrote:
Gas or diesel and towing what?

4:10s are only available in the DRW diesel in the 350. Need to step up to the 450 to get 4:30s. And the 450 only comes with the diesel.

4:30s only in the gasser.

[Grit_dog]

^ Lol, right?
Methinks the OP doesn’t know there’s a difference.
In short. Gasser, if towing anything significant, get the deepest gears you can for the best performance. Diesel has 2x+ the torque of the gasser so you can tow pretty heavy with taller gears easily.

[Lynnmor]

OK, its your secret about fuel. There is a large difference in RPM, and therefore required gear ratios between gas and diesel. Yes, I know that 4.10 is offered with some options, but I ain't looking it up.

[dennych1]

Looking at 2019 Ford dually f350. I would be towing occasionally but carrying a 5500 lbs truck camper

[Grit_dog]

Gas or diesel and towing what?