I have an 05 screw 4x4 with 3.73 gears I tow trailers and campers every week I run 275 70 18 tires (thinking of going 285 or 305) My question is would my towing fuel mileage suffer greatly if I went to a 4.10 gear right now I get anywhere from 9 to 12 mpg depending on the trailer and wind

 

4.10 you're not going to notice any difference.. Your vehicles performance depends on the owner first.. Normally before i tow long distance i change out the fuel filter, oill change, MAF cleaned ect.. Towing and MPG dont mix.. I'd sacrifice MPG for power anyday..

Bump up to 4.56 and you'll have plenty power but you probably won't see a big difference in highway MPG

 

You can use this to get a good idea of wear you will be.

 

forgive my inner dummy but what are the 4 digit numbers?

 

I believe thats what your rpms would be at around 70-75mph.

 

i'm running 35's with 3.73 gears and I sit at 1750 going 70, so this chart confuses me a little.

 

Dis you turn the over drive off?? It should shoot you up to 2100rpms

 

Makes sense now, if I look at it just before the torque converter locks it sits at the 2300 like it says

 

Thanks guys very helpful I am trying to find my line between power and mpg

 

I towed a 6,000lb trailer from New Orleans LA, to Pensacola FL, on 1 tank of gas running 80 mph on a 275/70/18 with 4.56... It's really not bad... And pulls hard.