i've been searching a few nights now, but after reading threads about gears, im probably more confused then before.

I have a 2008 2.3L 5spd reg cab. stock except for the 31" tires. Since adding the tires, the ranger, which was amazing on gas, absolutely sucks. I need my good gas mileage back, but im not getting rid of the tires, so, 4.10 gears seem the way to go...right? can somebody elaborate on 4.10s in the 2.3L? Also is the 31s straining the trans. or the clutch?

Also if i go for the 4.10s im thinking of getting a limited slip..is that possible? good idea? worth it? let me know.

 

drop in a 4.10 axle. it'll put you right about stockish feel and stockish mpg and 'seat of your pants' numbers. That route's alot cheaper than actually swapping the gears. If you do choose to swap the gears and not just find a 4.10 axle, I'd personally go for a 4.30:1 ratio on your truck.

bigger tires or higher gearing(numerically lower) puts more strain on the engine and clutch to get it moving and keep it moving. Right now you truck is driving like it has 3.30's in the axle.

rule of thumb:
-higher gearing(lower number) = better highway mpg, harder to get moving from a stop so it eats gas. sluggish around town.
-lower gearing(higher number) = better city mpg, funner to drive(more get up and go), less hwy mpg.

Those are the rules period, but getting it back to a proper gear ratio for the tires will jump everything up(mpg, power, etc).

 

what gears do you have now? Some 4 cylinders had 4.10s stock. Sometimes it is better to re-gear instead swapping in an old worn out axle too, especially since you only have one axle to deal with.

 

im pretty sure i have the 3.73s. My truck is SLOW to take off. im sure i dont have 4.10s. I thought about swapping in a whole axle, and im down for it, if i can get it from a fairly new truck. if not, i rather spend the money, knowing it'll be done right, rather than having some old abused axle, like mentioned above.

what about the limited slip? another thing i forgot to mention is the weight of rims. would the weight of rims slow me down much, or would rims not weigh much over stock to make a difference?

 

Larger tires will drop your gas mileage some, but you may be getting significantly lower numbers for two reasons if you have yet to recalibrate your speedo.

1) With the speedo off, you tend to believe the speedo when driving, forgeting to correct the speed in your mind. With larger tires you end up driving faster than you think, which will burn up more gas.

2) With the speedo off, so will the odometer and tripometer. Forget to correct for the tire size difference in your gas mileage calculations and the results will look artificially lower than they really are.

I've got 4.10 gears and went from 29" tires to 31" tires, and my mpg fell only 1mpg when I got the speedo fixed and 31" tires from what it was with the 29" tires.

BTW, I've had 4.10 gears in a 2001 with the 2.3L, 5sp, and stock tires, and it worked great. Driving it like a grandpa and all highway, never going above 55mph I could get 33.5 mpg with it. Regular driving was 24 mpg.

 

^^Why do I always forget that!?!?? lol. Yeah....calculations are off because of the tire diameter difference. For example, the speedo is showing 50 when you're actaully going 57. Same with the trip meter/odometer...it's showing 200miles traveled, yet in reality you've traveled 225. Those are just numbers i pulled out of my butt.