Wally39

In the latest Mustang magazine there is an article about a Mustang these guys are modding to make faster in the 1/4 mile. The interesting thing about it was when they changed the gears from 3.31 to 4.10 they had to make a new tune for it. This is for an automatic transmission. They said without the new tune the computer still thinks it has 3.31 gears and the tranny doesn't shift like it should and can burn it up. Just a warning to guys with an auto and have changed their gears.

moosestang

I'd like to think no one is driving around with 4.10's without changing the tune to atleast correct the speedo, but who knows. You speedo will be off by 15mph unless you change the gear ratio in the tune.

You don't necessarily have to make a new tune, it's an option you choose when you reload the tune. Now for autos it might be different.

s197richie

I would think that getting gears before getting a tuner or CAI/tuner combo is kind of doing your mods out of order...the CAI/tuner combo is usually the best first mod, then gears a bit down the road from there (you know, like the next day lol)...

Mikes_BLK_GT

It's user adjusted on the auto's too...