Coyote5-0

Hey Guys,

I am looking at getting 3.73's for my anemic '13 GT with 3.31's. I will have to get a tuner to change the gear ratio in the computer to make the speedo and odometer stay true. I know Ford will deny warranty claims if they see the ECM has been flashed... So if i change the program for the new gears, couldn't Ford potentially deny an engine claim, seeing that it has been changed at some point? I know the ECM tallies every time the ECM is flashed. Couldn't Ford warranty take an ECM image and see it has been changed and automatically deny a claim? Can they see what exactly was changed, or do they just see that it has been changed?

I'm just thinking of a situation where my engine fails (be it #8 failure or whatever), the dealer sends in the ECM image to Ford, Ford see's the original parameters arent there and that it has been flashed at some point, and automatically denies my claim...

5LHO

You don't flash the ecm to change gears, it's a setting. Ford can change your stock ECM to any gear ratio that came with the car factory, no sweat, no warranty issues. of course if you are coming to them with a blown up rear end you might get some pushback.

Coyote5-0

Well I see myself eventually tuning the car (which I know will void the warranty) so I want to get a tuner now and just do it myself instead of paying the dealer. Does the ECM record parameter changes AND flashes, or just flashes?

kn7671

So yes, while you can have Ford adjust your computer for another factory offered gear ratio without needing a custom tune to maintain your warranty, you you will need a Ford dealership to perform the rear gear install as well if you hope to maintain any warranty on the rear-axle assembly, and that will likely only be covered for 12 months or 12,000 miles from the time the gears are installed by Ford, voiding any remaining factory or extended warranty you purchased covering the rear-axle assembly.

texastboneking

actually any gear ratio. They just plug the number in if I recall correctly. They would still need to flash it with the new ratio

any parameter change to the ecm requires it to be flashed.

kn7671

An aftermarket Tuner does not have the same capability as what Ford can do, meaning if you do this with an aftermarket Tuner, you will have no choice but to load their Tune file along with the rear gear ratio parameter.

Coyote5-0

I'm not concerned with the rear axle warranty...just any warranty claim that requires sending in the ECM image to Ford for review. So basically it will show the ECM has been flashed, even if its just to change the parameters for the rear gears?

Ltngdrvr

So far, all that is recorded in the pcm are "events", doesn't tell them what the event was.

They then go through a process of elimination to try and determine if the "event" was an aftermarket tune.

And this would only be if some damage was thought to be caused by someone loading an aftermarket tune.

And the whole warranty is not voided, only warranty on affected parts/systems.

And the dealer tech does "flash" the pcm for a ratio change and can only do it for originally available gear ratios, and they flash a whole new pcm calibration, not just a gear ratio change.

Coyote5-0

Welp, it looks like I might as well get an aftermarket tune and gears!!

GrabberBlue5.0

If the gears were not a factory option they cannot change it so you would need to get something else like an SCT tuner.

texastboneking

Been a while since I had my hands on an ids... for some reason I thought you just punched in the ratio you had in.

Ltngdrvr

Earlier pcm's were like that but not the new one in the Mustang.

Coyote5-0

any tuners you guys recommend?