6 speeds, can we drop out interstate rpm's with differential gearing ???

So I have a 2005 dbl cab, sr5, 4x4, 4.0L, 6speed.

I have searched on here and found answers like "drive slower"
but thats not really an answer. if thats your answer, then you are not helping the situation.

If we change from 3.73 to maybe 3.55 or 3.42 wouldnt this keep our rpm's lower? Assuming that we run stock tire size, and dont need to tow anywhere the limit. The v6 has plenty of power.

Seeing how all the gears in this 6speed are really low would this be the answer to high freeway rpm's?

The problem is I can find plenty of info and parts to gear for larger tires, but what im asking is essentially backwards

 

Actually driving slower is an answer it just may not be for you. That being said, yes changing the gearing will lower RPM and it may improve MPG depending on the person doing the driving.
If you do it let us know how much you gain or lose.

 

^ I know what you mean, but Keeping it under 55mph to save gas when the flow of traffic including tractor trailers is 80mph. Thats just a bad idea idea...


My googling, has only led me to find more extreme ratio gears. Im wondering what to look for. anyone know of a brand or search words?

 

Larger diameter tires effectively changes the final drive ratio

 

And increases rotating mass and unsprung weight. In most cases those factors outweigh any positive gain.

 

big tires

 

Swap in a ring gear from a 5lug and you should be golden. I actually want to swap to 3.73's. Wanna trade? I got dibs on you sending me your stock ring gear first.

 

Yeah, swapping the rear gears is probably your only option. Like someone else said, putting on bigger tires will do much more harm than good.

 

Just add a 7th gear to the tranny and you'll be set! I've heard it's easiest to contact Harry potter for the work.....

 

^ no shlt thats what this search seems like... quarter of a million places want to put 4.10 but never heard of someone going the other way.

 

I have never actually done the work myslef... Where is the write up on that LoL? What year 5lug? any year 4x4? what ratios do they have?

 

yes

 

Just remember that changing your rear axle ratio will definitely drop your rpm at highway speeds, but it will also effect the performance at takeoff and when going uphill. I think having a standard will be a benefit if you do it.

 

1st gear is so low on this thing, I didnt even need to use it with a motorcycle and generator in the bed. 2nd gear take offs are almost where 1st gear should be for street use.

 

Sounds like new gears might be just the thing for you.

 

Here is a link on the axles, I believe X runners are @ 3.15ish, I think bases are around 3.30's, and then 6lugs are at 3.73.

http://home.4x4wire.com/erik/diffs/

 

Changing the gearing can lower the RPMs but depending on what speed you want to cruise at, you might lower the RPMs to where you are out of the best efficiency part of the torque curve and actually use more gas. Too many variables (tire size, desired speed, differential gear ratio, transmission gear ratio, mods that add weight to your truck, fuel quality, aerodynamics, etc....) to be certain of what is going to be the best solution for your fuel consumption goals.

 

back to google...

 

Dont put it in 4x4

 

Ya, looks like i cant find anything for the front diff. Im sure there is a setup out ther from something.

All the shops here are quick to say "no, nothing would work"

guess they dont know what they are doing down here. I might have to call back home to Cali and talk to an expert.