Best gears for an Auto??
 

I just made the switch to 3.73 gears...I have not track tested them yet but for day to day driving, I love them!!! I know with the boss intake, you will enjoy them even more as it will help with the low end torque loss. Just make sure you have good, wide tires.

What gears do you currently have?

How do you tell what gears you have? At 2k rpm I am right at 70mph.

-Alex

4:10s

Are you sure?? That's the lower gears available from the factory... Most torque in those gears. Why the change? That's a better question, are you looking for low end or all around?

There is a tag on the axle if you can decipher it. There is also a vin decoding website, although I don't know what it is. Do you have the window sticker? It also has it...

3.31 seems to work best up until you trap 126mph or so, then you either need a 30" tire or go back to stock 3.15.

No window sticker. Car was not purchased new. Guess I could just ask a dealership.

-Alex

It came with 3.15, they all did.

Thanks.

-Alex

Basically all around I want a good aggressive gear at the track but that's also good for hwy racing.

Mine came factory with 3.31s, and my brothers came with 3.55s... I've also driven a 2012 with factory 4.10s...

No 2011+ automatic ever came with anything but 3.15. No 2011+ ever came with 4.10. Manuals are 3.31, 3.55, or 3.73.

I would go with 3.55s, just as a good medium. You won't see extremely excessive gains or losses.

Ya, somehow completely forgot we were on autos.... Wouldn't you have to reset the adaptive values in the TCM if you changed gears??

The 4:10s are aftermarket

The problem with a gear like 4.10 and this trans is traction. I did run a 4.30 for a long time and on the rare occasion it would hook it was badass the way it picked up the front end. The 3.31 just made it a better car, it was just as fast, and it goes down the track every time now. Think of it this way, let's go old school C-4 trans, those had a 2.46 1st gear. The 6R80 has a 4.17. So, 4.17*4.10=17.097 ratio in 1st gear. Now try to get a C-4 the same. 17.097/2.46=6.95. You'd agree a C-4 and a 6.95 is a hell of a lot of rear gear right? That's the same you're getting with a 4.10 and a 6R80. Even the stock 3.15 gear is like a 5.34 axle with a C-4. If you wondered why these automatics run so good, right there is a big reason why. Leave the stockers in it, or maybe change to 3.31 to get the very slightest bit more out of it.

I'd say you won't make it in 3rd unless the car runs a really low trap speed, or unless you put a really tall tire on. 3.31 with a 28" is the best bet for most cars to be able to trap in 3rd. Once you get to like 126-127 MPH, time to start thinking about 3.15 with a 28" or 3.31 with a 30" tire.

StangFreak, you're probably thinking of my red auto. Had a Boss intake and 4.10s and always crossed the finish line in the middle of 4th...not ideal. Went to 3.31s and cross the finish line at the top of third saving time to make that last shift, easier to launch, have great gas mileage again (just in time for e85!)

Oh yeah i haven't gotten the car to hook off the line and the extra mpg wont hurt, this is with the RPMs set @ 7700? If I happen to run into used 3:31s would I have any issues with them oppose to ordering new one from AM ? And can they be set to have a" kick" as I like to say, I like how the 4:10s feel.

Thanks

I shift around 7700 and the kick is all in the tune my friend ;)

Used gears can sometimes be risky due to the wear on them. I'd go new Ford Racing ones purchased from anywhere reputable. As mentioned before the "kick" is in the tune. The 4.10s do have a kick due to the torque multiplication but it'll depend on the goals you have but 3.31s work better for me with what I am trying to do

I've had no problem with used 3.31 from newtakeoff.com, in more than 1 car. They are $80. It's all about having the right tools and knowing how to use them.

Thanks for the info guys :cheers: