To give an idea of what you can expect.....for every .25 ratio gear change, the rpm's change by 300 rpm.

 

I am also looking at gears for my 2007. I have 35's on a 6" lift currently with 3.73LS. I was leaning towards the 4.10 given that Ford uses them on the Raptor but now reading that the new transmissions are different and mine is a four speed, maybe I should re-think going with the 4.56's after all? I drive a fair amount of highway miles to my wheeling spots but also climb the Sierras to get to Nevada from California and then do desert wheeling. I usually have a pretty good load of camping gear in the back as well.

 

im wanting to go with 4.88's or even 5.13's if i can find a set for the front diff, but i read that the retaining pin for 4.88's is larger than the 4.56's and i would need to buy an aftermarket one in order to make the gear set fit correctly inside the diff.

 

i got 33's on a 4.6 auto...what gears should i get...if any...she works ok. still gettin good mileage...i kno im a noob. i have a 3.55

 

So, to go from stock gears to 4.56s on a 2004, I NEED a tuner?

 

Highly recommend it as if u don't your speedometer will be way out of whack and need to be recalibrated for both speedometer and transmission shift points.

 

Good point, however, regearing is to expensive.

 

Even just a tuner will help as u can put in the size of tire and help to correct where the transmission needs to shift. On my diablosport its called nov for engine over vehicle speed. You calculate by using the circumference of tire and axle ratio. This helped significantly after I put larger than stock tires on. Then I also changed the tire size, which calibrated the speedometer. Got my programmer for under 300, which I would recommend trying before regearing. Not going to push u get same programmer as me, as that will start a whole new debate, but a programmer in general would help out.