Final drive ratio
Logistics Pro
Joined: May 2017
Posts: 3,523
Likes: 483
From: Southern OH
You are not gonna believe this, but these auto transmissions they put in the SDs these days, they automatically downshift when ECM and TCM decide it's time for some torque multiplication.
If you really want to go plebian, you can also downshift it yourself. But that's very advanced technique that only the pro drivers know how to do.
If you really want to go plebian, you can also downshift it yourself. But that's very advanced technique that only the pro drivers know how to do.
Logistics Pro
Joined: May 2021
Posts: 4,036
Likes: 2,345
Yes I prefer to shift it myself, you get more torque and it's easier on the driveline to move the load with a lower rear gear in the same transmission gear as it is with a higher rear gear. What is the advantage of a gas engine to get 3.73s instead of 4.30s? None that I have found, plenty of disadvantages though.
I ask again, what load are you towing that 3.73 with the 10 speed would have a hard time to get moving? Reality check: if a load and/or incline is heavy/steep enough to damage drive line on a 3.73, your precious 4.30 is not gonna come out of it unscathed, well, maybe 15% less damaged but you still have to replace the damaged parts. LOL.
5th Wheeling
Joined: Jul 2023
Posts: 33
Likes: 3
I guess this thread is about gas drive ratios. I just want to say that I am going to own a first ford superduty ever of my life. In fact first ford ever. I plan to tow a 12,000 lb travel trailer. The truck is going to be a 2024 f350 with 3.55 gears behind the 6.7 diesel HO. I have full confidence in this. I can't imagine that gas engines will be far too different. If I had the option, I would have considered gas. The limited only comes with diesel.
Useless reply, I know.
Useless reply, I know.
Logistics Pro
Joined: May 2017
Posts: 3,523
Likes: 483
From: Southern OH
Lower rpm when the engine doesn't need to turn 15% more RPM to get the job done?
I ask again, what load are you towing that 3.73 with the 10 speed would have a hard time to get moving? Reality check: if a load and/or incline is heavy/steep enough to damage drive line on a 3.73, your precious 4.30 is not gonna come out of it unscathed, well, maybe 15% less damaged but you still have to replace the damaged parts. LOL.
I ask again, what load are you towing that 3.73 with the 10 speed would have a hard time to get moving? Reality check: if a load and/or incline is heavy/steep enough to damage drive line on a 3.73, your precious 4.30 is not gonna come out of it unscathed, well, maybe 15% less damaged but you still have to replace the damaged parts. LOL.
Logistics Pro
Joined: May 2021
Posts: 4,036
Likes: 2,345
Since you continue to refuse to clarify what you actually use it for, I then have to assume your belief in 4.30 is a simplistic, one dimensional belief that ignores all the other advances Ford has implemented in their engine, transmission, driveline, etc areas. Ask yourself, did you buy a truck to do a job, or did you spec it because you have always spec'ed it a certain way in one very specific area and you just can't fathom technology has moved on from your assumptions? If more available torque at any given time is the one an only goal, we should all just man up and drive F450s with the PSD and 4.30 rear end, don't even bother with all this girly SRW wimpy gas nonsense or those old 7.3 PSD that are anemic at best.
Logistics Pro
Joined: May 2017
Posts: 3,523
Likes: 483
From: Southern OH
That is patently false. It allows the engine to turn over less when the condition does not require the motor to turn over as much as the 4.30 requires it to at the top end. If there is no appreciable difference, Ford would be putting in 4.30 in all their SD trucks, gas or diesels.
Since you continue to refuse to clarify what you actually use it for, I then have to assume your belief in 4.30 is a simplistic, one dimensional belief that ignores all the other advances Ford has implemented in their engine, transmission, driveline, etc areas. Ask yourself, did you buy a truck to do a job, or did you spec it because you have always spec'ed it a certain way in one very specific area and you just can't fathom technology has moved on from your assumptions? If more available torque at any given time is the one an only goal, we should all just man up and drive F450s with the PSD and 4.30 rear end, don't even bother with all this girly SRW wimpy gas nonsense or those old 7.3 PSD that are anemic at best.
Since you continue to refuse to clarify what you actually use it for, I then have to assume your belief in 4.30 is a simplistic, one dimensional belief that ignores all the other advances Ford has implemented in their engine, transmission, driveline, etc areas. Ask yourself, did you buy a truck to do a job, or did you spec it because you have always spec'ed it a certain way in one very specific area and you just can't fathom technology has moved on from your assumptions? If more available torque at any given time is the one an only goal, we should all just man up and drive F450s with the PSD and 4.30 rear end, don't even bother with all this girly SRW wimpy gas nonsense or those old 7.3 PSD that are anemic at best.
Logistics Pro
Joined: May 2022
Posts: 4,295
Likes: 2,417
From: Everywhere and nowhere
Like I said before with 4.30 gears running 75 MPH you are already turning an RPM that is well below the torque peak of the 7.3, 3.73 gears would put you even further away from that so no advantages there. The only reason the offer 3.73s is to appease the group of people who are stuck in the 90s and automatically think that a higher rear gear ratio means you get better fuel mileage however that is simply not the case in the majority of situations with modern engines and drivetrains. Back when trucks came with 31" tires and only a .71 OD ratio it made more sense to get the 3.73s over 4.30s if you were going to be driving unloaded most of the time and only tow light. Now with them coming with 33-35" tires and a .63 OD ratio there is no reason to get 3.73s since 4.30 gears already has you at a low enough RPM as is.
At 70mph in 10th gear I'm turning between 2000 and 2100pm with 4.30s and 31.5" tires. That is high and unnecessary for long trips at high speed. Both gear ratios under the 7.3 got the best fuel economy around 1600-1700rpm once the converter locks up. There is zero need for peak torque at 75mph. You only need as much HP and TQ are required to move the load at 75mph.
Logistics Pro
Joined: May 2021
Posts: 4,036
Likes: 2,345
Like I said before with 4.30 gears running 75 MPH you are already turning an RPM that is well below the torque peak of the 7.3, 3.73 gears would put you even further away from that so no advantages there. The only reason the offer 3.73s is to appease the group of people who are stuck in the 90s and automatically think that a higher rear gear ratio means you get better fuel mileage however that is simply not the case in the majority of situations with modern engines and drivetrains. Back when trucks came with 31" tires and only a .71 OD ratio it made more sense to get the 3.73s over 4.30s if you were going to be driving unloaded most of the time and only tow light. Now with them coming with 33-35" tires and a .63 OD ratio there is no reason to get 3.73s since 4.30 gears already has you at a low enough RPM as is.
My 3.55 with 33 inch goodyear AT tires tows 10k just fine, 12k is no issue either, I get 18-19mpg at 65mph when not towing but still have about 500-1k in the bed.
If you find yourself relying on 4.30 behind a 7.3 gas and 10 speed just to tow up to 14-15k, perhaps it is time to re-learn how to drive.
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Hotshot
Joined: Jun 2003
Posts: 12,355
Likes: 4,390
From: SW VA
I lock out gears until I'm at lest running 1200-1500.
Logistics Pro
Joined: May 2021
Posts: 4,036
Likes: 2,345
If that 150RPM makes that kind of difference between lugging and not lugging, you need to get your truck in to a shop to check if there is a problem. LOL.
Logistics Pro
Joined: May 2017
Posts: 3,523
Likes: 483
From: Southern OH
LOL.
My 3.55 with 33 inch goodyear AT tires tows 10k just fine, 12k is no issue either, I get 18-19mpg at 65mph when not towing but still have about 500-1k in the bed.
If you find yourself relying on 4.30 behind a 7.3 gas and 10 speed just to tow up to 14-15k, perhaps it is time to re-learn how to drive.
My 3.55 with 33 inch goodyear AT tires tows 10k just fine, 12k is no issue either, I get 18-19mpg at 65mph when not towing but still have about 500-1k in the bed.
If you find yourself relying on 4.30 behind a 7.3 gas and 10 speed just to tow up to 14-15k, perhaps it is time to re-learn how to drive.
Logistics Pro
Joined: May 2017
Posts: 3,523
Likes: 483
From: Southern OH
But you do get better fuel economy with the 3.73s vs 4.30s with today's engine, transmission and programming. I know first hand.
At 70mph in 10th gear I'm turning between 2000 and 2100pm with 4.30s and 31.5" tires. That is high and unnecessary for long trips at high speed. Both gear ratios under the 7.3 got the best fuel economy around 1600-1700rpm once the converter locks up. There is zero need for peak torque at 75mph. You only need as much HP and TQ are required to move the load at 75mph.
At 70mph in 10th gear I'm turning between 2000 and 2100pm with 4.30s and 31.5" tires. That is high and unnecessary for long trips at high speed. Both gear ratios under the 7.3 got the best fuel economy around 1600-1700rpm once the converter locks up. There is zero need for peak torque at 75mph. You only need as much HP and TQ are required to move the load at 75mph.
Hotshot
Joined: Jun 2003
Posts: 12,355
Likes: 4,390
From: SW VA
Why are you so triggered about this? You are cheerleading 3.73/3.55 much harder than anyone has ever praised 4.30's, but you can't see it because of your bias. Why do you promote less power to the wheels so intensely?
Logistics Pro
Joined: May 2022
Posts: 4,295
Likes: 2,417
From: Everywhere and nowhere
you switched to 4.56s and 35s on an alumiduty with a 7.3 gas engine and a 10spd? If so you did not gain any mileage.
Logistics Pro
Joined: May 2017
Posts: 3,523
Likes: 483
From: Southern OH
Hand calculated. 35" MT tires with 4.56 gears gets better mileage than the same 35s with 3.73s did. It did get better mileage with the stock street tires and 3.73s.