I have a 2013 GT Premium Convertible 6-speed with factory 3.31 gears without any kind of tune. I want to install 3.73 gears and know that the speedometer has to be recalibrated. Problem is I've contacted five local dealers. Three told me that Ford has the computer locked and they cannot change the ratio (can that be?). One told me that they "might" be able to make the change but wouldn't but wouldn't know for sure until they put it on the machine. The last dealer recommended a local "tune" shop. Suggestions will be appreciated!

 

From what I've read, they should be able to do that at the dealer. The service writers you are talking to probably have no idea what you are really asking for, or what a rear gear set is. You really dont need to know anything about cars to work as a service writer. I've worked for enough dealers/shops to know this. Their favorite quote was "if you can't dazzle them with brilliance, baffle them with bullsh*t!"

But I have also only owned my '13 since May and have only been heavily following these forums since then.

BTW, you can buy your own custom tuner and do it yourself. Any changes to the original ECM software will likely void your engine warranty though

 

Hello Old Sailor,

You should try to contact one of our FRPP authorized dealers here, and check with them.

Deysha

 

I changed the rear gear to a 3.73 on my 05 auto GT. I used a bama tune and an SCT tuner. I was able to adjust the speedometer for the gear I was running and what a difference !!! It was like a completely different car.I would email or phone SCT in Florida, or American Muscle. They have 2013 tunes and I run them in my 13 GT.

 

^^^^^^^+1 Deysha is "right on." I found that my local FRPP dealer, although not where I bought the car, was very "aware" and knowledgeable about modifications I was interested in on my 2013 GT convertible. They definitely can adjust the diff ratio in the ECU programming to correct your speedometer. You may or may not have to pay for a FRPP tuning tool to make that change. With the tool they can change the diff gear ratio in the ECU without changing anything else, or they can install the FRPP tune as well. They key is getting to your FRPP dealer to have the discussion on the options.

 

Thanks for the suggestions!!

 

When I bought my SCT xcal2 I had it set up with a 87 performance {to get rid of throttle lag issues}, a 91 performance and a completely stock tune installed so I could run the stock tune and still mod the speedometer for different gear ratio's if I wanted.

 

This thread makes sense. I've read in other posts that Ford could only recalibrate the 3:31 rear gear change, as that was all that was offered in a "performance" package. This seemed dumb, as most tuners sold today can change the speedometer with a gear change, so why not Ford?

I'm guessing it's the service writers that simply may not know.

 

The car in question is a GT according to the OP's sig.

Answered this question over on AFM, the dealer cannot reset individual pcm parameters like the gear ratio or tire size, what they can do is a pcm reflash to a program from a different pcm code from a Mustang with the correct gear and tire size to match the new gear, but only if it was originally available on the car.

So, on a 2011+ GT they can reflash the pcm for 3.31, 3.55 and 3.73 gears and that's all.

Now, some dealers, or at least some service writers, don't know that this capability is available to them.

 

You State side folks sure seem to have trouble with dealers. I have had nothing but excellent service any where I have gone in western Canada.

It does cost though - diesel pickups and speedy cars require a significant pay grade!

 

And, some dealerships simply refuse to make any change to the car, or the ECU program, that wasn't standard when the car was built at the factory. I had a dealer refuse my request for a change. That's when I went to the primary FRPP dealership in the city. They were happy to make the change and explain the impact on the warranty (This was not the dealership where I bought the car).

 

My dealer said they would charge $85 to fix my speedometer if I got my gears changed to 3.73 elsewhere. ..

 

My dealer said, I got a rock....