tremor 7.3 gas motor gears

[Boogieman]

I went to order a Tremor and my dealer tells me with the gas motor you can only 4.30 gears. You have to get the diesel to get 3.55 gears. The 4.30 sounds way to low for me.

 

[BigBill]

I went to order a Tremor and my dealer tells me with the gas motor you can only 4.30 gears. You have to get the diesel to get 3.55 gears. The 4.30 sounds way to low for me.

Hi Boogieman,
Yup both Gas and Diesel have a single (read NO choice) option for gearing with the ratios as you stated. Having owned larger trucks with big tires the added rotational mass significantly reduces performance. To maintain a reasonable tow and payload rating, as well as customer satisfaction for acceleration, the ratios chosen are best suited. The mitigating factor here is the 10 spd transmission which allows for a broad spread of complete end to end ratios (crankshaft to wheel) which should help with towing and MPG concerns.
If it really bothers you remember you can simply swap in your gear of choice and re-program the ECU (Superchips, Bully Dog, etc) for speedometer compatibility.

Personally I am not buying my truck for mileage and will simply "suck it up" at the pump. Bigger concern for me is the question of when modding whether I am willing to handheld tune for a 5-10% power increase but then needing to step up to premium fuel.....

 

[Boogieman]

Hi Boogieman,
Yup both Gas and Diesel have a single (read NO choice) option for gearing with the ratios as you stated. Having owned larger trucks with big tires the added rotational mass significantly reduces performance. To maintain a reasonable tow and payload rating, as well as customer satisfaction for acceleration, the ratios chosen are best suited. The mitigating factor here is the 10 spd transmission which allows for a broad spread of complete end to end ratios (crankshaft to wheel) which should help with towing and MPG concerns.
If it really bothers you remember you can simply swap in your gear of choice and re-program the ECU (Superchips, Bully Dog, etc) for speedometer compatibility.

Personally I am not buying my truck for mileage and will simply "suck it up" at the pump. Bigger concern for me is the question of when modding whether I am willing to handheld tune for a 5-10% power increase but then needing to step up to premium fuel.....

I agree with you with 35 tires and ten speed hopefully it will be ok. I travel up and down the east coast about four times a year and would have liked a 3.73 gear. But a 6.7 diesel you can get 3.55 gears. However $10,000 in fuel goes a long way.

 

[Raspy]

The 4.30 rear end ratio should be the perfect setup. There is a lot more to the story than simply the final drive ratio, and putting in taller gears does not always mean better mileage. Look at the top OD ratio in the tranny, look at the diameter of the tires. Look at the power band in the engine. 3.55 would suck with the 7.3 One of the reassons I went with the Tremor was because it has the 4.30. And the comparison to the diesel gears means nothing. If you disagree, as was mentioned, regear it later.

 

[7.🌲]

Maybe an fx4 7.3 with lower gears, lower ride height and low front valance for improved aerodynamics may be a better alternative?

 

[Langosta39]

The 3 overdrives in the 10 speed make the 4.30 not feel so low on the highway. In my Tremor 7.3 I turn barely over 2000rpm at 75mph. And I have crazy torque off the line when towing or playing!

 

[7.🌲]

Came across this...7.3 tremor.

 

[Cococounty]

Didn’t know you couldn’t get 3.55 in the gasser I had to look around to get it in my diesel but it helps on gas must be like you guys said power ban

 

[BigJack601]

My tremor with the 7.3

 

[2020Tremor]

I went to order a Tremor and my dealer tells me with the gas motor you can only 4.30 gears. You have to get the diesel to get 3.55 gears. The 4.30 sounds way to low for me.

I came from a GM big block witch originally had the higher 3:73 gears, after running the lower 4:10s I am not a fan of the higher gears when towing or off road. Throw bigger tires into the mix and in my experience higher gears can produce worse economy than lower gears. Increasing tire size effective ratio goes up, couple that with the increased rotating mass and can really eat in to the overall performance when geared higher. I suspect that is why Ford only offers the lower gears on the Tremor.

I agree with Raspy you can’t compare gas and diesel gearing. The vastly different rpm ranges where power is developed in the engines makes different gears more practical for each engine.

I am really liking the 4:30s in the Tremor, responsive on the trails and tows really well.

 

[ShiverMeTimbers]

I think your highway speed is going to factor into this. Here in Washington state I usually never go over 75. Other places I've lived, everyone drove 80 to 85. If I keep it under 75 my mileage is best. If you drive over 75 regularly with a 7.3 gasser and 4.30 gears, you're going to see your mileage take a hit.

I love the 7.3 and 4.30 gears with a 10 speed transmission. So much range and versatility.

 

[mbe]

Motto: learning forever...what is gear if you can explain, please?

 

[2020Tremor]

I think your highway speed is going to factor into this. Here in Washington state I usually never go over 75. Other places I've lived, everyone drove 80 to 85. If I keep it under 75 my mileage is best. If you drive over 75 regularly with a 7.3 gasser and 4.30 gears, you're going to see your mileage take a hit.

I love the 7.3 and 4.30 gears with a 10 speed transmission. So much range and versatility.

Living in a state with 80mph speed limit everything I have driven has taken a mileage hit at 80+ vs 75-. Yes you have to spin more RPM to hold that speed but wind drag is a huge factor is decreased economy as well. The forces seen by drag are puportional to the velocity squared, translation that extra 5 mph has a huge effect on drag and going to require more power to overcome it than just the RPM increase.

 

[Dissident]

As said above gears by themselves are just a number.

You have to calculate the whole driveline to get mechanical advantage. The gas has a 53:1 crawl ratio and the diesel is around 48. I dont know what the high speed numbers are but max fuel economy on the 7.3 is probably around 58 mph.

Example:
my tundra had 4.3 gears but if you did the math the ford f150 with 3.73 gears still had better mechanical advantage.

 

[2020Tremor]

My tremor with the 7.3
View attachment 13736

I was able to get a comparison this morning at 80 for reference.

 

[Raspy]

I'm impressed that the 7.3 will stay in 10th at 80 MPH and only be turning 2200 RPM. That engine is tuned for low end torque. Perfect. That means good volumetric efficiency.

It means it will get good mileage, for what it is, because it's running efficiently and at that power level has a low intake vacuum (closer to atmospheric). Good cam timing (volumetric efficiency), tall gears (low internal friction) and low vacuum (not working against itself), a great combination for rolling along the highway.

I used to think 10 gears was too many to make sense. But I'm coming around. It means the engine can be run as slow as possible to do the job and can be held in a very narrow RPM window for best efficiency. Looking at the ratios, this tranny has a very wide range, from a very low, low, to a very tall high. And it's shifting is nice too. Shifting itself is not an efficient process, but in this case, it can skip gears up or down to reduce that problem.

 

[sokoloka]

Can always do a little rubber overdrive if you're looking to drop the RPM's and step up to 37's

 

[Raspy]

Can always do a little rubber overdrive if you're looking to drop the RPM's and step up to 37's

That will give much worse mileage, worse braking, and worse throttle response. The engine computer will have to be reprogrammed to make it shift correctly. But it might wheel better in some situations, like sand. Taller gearing will not help this truck.

 

[BigJack601]