gearing question

[Christopher Comeaux]

if i go from 4.10 to 3.73 will it be good in any way to me

i tow my camper and small utility trailer everynow and then

im looking to see what u guys think

will 3.73 or save me fuel and i still be able to tow with no problems

 

[Jerry Gerner 2]

Your speedo will be off and you'll lose your gearing for when your towing. I wouldn't do it myself but that's just my opinion.

 

[EddieS'04]

I say no. It will take more engine rpms to get the same TQ multiplication. To get the load moving. Even if you go to the smaller tire. Your back at the the same gearing.

 

[Christopher Comeaux]

ok so its a bad idea?

 

[Christopher Comeaux]

im mainly looking to get my mpg better

 

[Johnny O]

Modern OHC engines actually need a little rpm to run at their most efficient level. I went from a Ranger 4x4 with a 4.0 SOHC and 4.10's, awful on gas, to my first Sport Trac, an '05 with a 4.0 and 3.73's. I immediately added a TT/shackle lift and 265/75-16's to run the motor slower than my Ranger's did, and it wasn't really any better on gas anyway. In fact once I towed my jetski to a lake in Maryland, left the OD off, and it seemed like it used LESS gas that way.

 

[Yardsale]

Probably not. That change, if the only change, will most likely drop the engine RPM at freeway cruise speed below the engineered power band and cause you to compensate by accelerating, which causes downshifting (due to the programming). The result could be continual shifting, especially on up hills and decrease fuel mileage. You will not like it.

 

[Todd Z]

Find a set of Larger tires and try it.....



IF you have factory 255/70/16 get a set of 275/70/16 and the tire height change will act like the 3:73 gear ratio..........



BUT you MUST correct your speedo for it to be accurate..



Todd Z

 

[TRACket Paul]

Yardsale, Since Ford makes the 3:73 differential as an available option, how would it not be in an "engineered power band:?

 

[David Ponder]

Paul, I think the 4:10 gearing setup came with different Factory tire size than the 3:73 gearing. Just going off a vaigue memory there..

 

[Christopher Comeaux]

i have factory 255 with 4.10 so if i do 275 it would be the same as putting 3.73?

 

[Johnny O]

Yardsale, Since Ford makes the 3:73 differential as an available option, how would it not be in an "engineered power band:?

Paul, I think the 4:10 gearing setup came with different Factory tire size than the 3:73 gearing. Just going off a vaigue memory there..

Gen 1 Tracs with 235/75-15 or 235/70-16 tires came with 3.73 gears. I used to have one. Gen 1 Tracs with 255/70-16 tires came with 4.10 gears. RPM vs. MPH would be about the same either way.

Much cheaper to just buy taller tires instead of changing gears. Just allow for the fact that your speedometer and odometer will be off when calculating the MPG.

 

[Johnny O]

Duplicate post.

 

[Tom Schindler]

Same gas mileage. You are wasting your time and money.





Tom