4.09 gears help

[Krusin5.0]

????

sorry on my phone. All tuners that replied said to just take it to the dealer and they will flash it to accept the new gears.

2 of them said the BDX does not have the ability to update it correctly and the dealer should do it for no charge due to them not advising customers that it will require an update before it will work.

called my local ford and they are going to get back to me. I will have them update what is required and add the tune once it arrives.

my local ford said that is why they discontinued the 4.09 gears through ford performance. To many customers complaining and ford having to resolve it on their dime.

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[Angrey]

Can someone clarify a question that's been proposed with these swaps.

As I understand it, you can adjust the ratios in Forscan or you can adjust them in the "tune." However, if you adjust them in the tune, then it overrides FORSCAN and then can no longer be adjusted that way. Am I understanding that correctly?

And would NOT updating it affect the torque calculations/limits for each gear? I understand it'll throw the car off with speedo but will it give the computer fits with the torque tables?

 

[Krusin5.0]

Can someone clarify a question that's been proposed with these swaps.

As I understand it, you can adjust the ratios in Forscan or you can adjust them in the "tune." However, if you adjust them in the tune, then it overrides FORSCAN and then can no longer be adjusted that way. Am I understanding that correctly?

And would NOT updating it affect the torque calculations/limits for each gear? I understand it'll throw the car off with speedo but will it give the computer fits with the torque tables?

Forscan will not work, it needs an update that the car will not receive unless it is a PP car. I tried forscan, will not work, tried the BDX tuner which has an option to change tire and gear ratios.

forscan and BDX only works to change the gears, if it has the PP tune applied already. If I use either I get a p0621 and U0422 codes and car goes into limp/service mode.

Only option is take it to the dealer for the flash or get a custom tune not on a SCT device.

 

[K4fxd]

Only option is take it to the dealer for the flash or get a custom tune not on a SCT device.

I'm surprised SCT does not have the max ratio table defined.

 

[Angrey]

Forscan will not work, it needs an update that the car will not receive unless it is a PP car. I tried forscan, will not work, tried the BDX tuner which has an option to change tire and gear ratios.

forscan and BDX only works to change the gears, if it has the PP tune applied already. If I use either I get a p0621 and U0422 codes and car goes into limp/service mode.

Only option is take it to the dealer for the flash or get a custom tune not on a SCT device.

I think it's more complicated than that, which is why I'm asking, because there are other threads out there where people have adjusted their ratios/tire sizes through FORSCAN (successfully) and those who have been unable.

I think it has to do with how it's addressed within the tune. Once a particular feature of the tune is in place or active, it will not allow (or ignores) the FORSCAN inputs.

 

[K4fxd]

Looks like HP tuners just bricked version 4 on the MPVI2. My scanner quit working and when I reinstalled the software I lost several parameters. Still won't scan my car.

On my other machine running the 5.1.0 version everything works just fine.

 

[junits15]

Can someone clarify a question that's been proposed with these swaps.

As I understand it, you can adjust the ratios in Forscan or you can adjust them in the "tune." However, if you adjust them in the tune, then it overrides FORSCAN and then can no longer be adjusted that way. Am I understanding that correctly?

And would NOT updating it affect the torque calculations/limits for each gear? I understand it'll throw the car off with speedo but will it give the computer fits with the torque tables?

They need to agree

The ECM reads from the BCM, there are limits built into the ECM that need to be modified in order to go up to 4.09. The stock upper limit (at least on my car) is 3.77. The BCM can be manually programmed to the gear ratio and the ECM can too. If they agree it will work.

This is why you see some swaps working, you can swap to 3.75 with just a BCM change.

The torque calculation will remain "plausible" but incorrect. Will probably reduce the effectiveness of your traction control, but that would be it. No major issues, no show stopping issues on that front.

 

[Ruiner46]

Looks like HP tuners just bricked version 4 on the MPVI2. My scanner quit working and when I reinstalled the software I lost several parameters. Still won't scan my car.

On my other machine running the 5.1.0 version everything works just fine.

What do you mean by this? Did they force a firmware update to the MPVI2 device itself?

 

[K4fxd]

What do you mean by this? Did they force a firmware update to the MPVI2 device itself?

If it did it was in the background. I stupidly allowed my tuning computer to connect to the internet and ever since I cannot get the scanner to work, and it now wants me to update to the x64 version. I am going to try a complete reset of my laptop and reinstall version 4.

 

[Krusin5.0]

The ECM reads from the BCM, there are limits built into the ECM that need to be modified in order to go up to 4.09. The stock upper limit (at least on my car) is 3.77.

this is what I am assuming is going on in my case. I am capped at 3.77 and the 4.09 is out of that range so causing problems.

I cannot trick the car by changing tire size as going from 3.31 to 409 the tire size pushed it out of bounds same as the gear ratio

wonder if setting it to 3.73 and change tire size. That might work.

 

[junits15]

this is what I am assuming is going on in my case. I am capped at 3.77 and the 4.09 is out of that range so causing problems.

I cannot trick the car by changing tire size as going from 3.31 to 409 the tire size pushed it out of bounds same as the gear ratio

wonder if setting it to 3.73 and change tire size. That might work.

Tire size changes the distance traveled on the edge of the tire, the RPM of the axle is always the same for a given engine RPM. You'll be in the same situation unfortunately.

It is easy to see why that might seem like it would work, but in reality tire size causes a speedometer error because it increases vehicle speed for the same axle speed and driveshaft speed. Whereas increasing the final drive causes a speedometer error because it increases axle speed for the same driveshaft speed.

I think the fact that it causes an error at all indicates that the car is making its speed measurements at the output of the transmission, not at the hubs.

 

[Krusin5.0]

Update, tune is in the mail but while I wait. I decided to contact Fords head office. Needless to say, after a lengthy conversation they contacted Ford performance. They are sending the calibration files to my local Ford dealership. About 10 minutes after I get off the phone with Ford Canada, my local dealership calls me and says I have an appointment for this coming Wednesday at 10am.

will update everyone after my appointment.

 

[Krusin5.0]

Tune finally arrived and she works as it should now also ford performance has updated the description on the gears and have included it below.

“ Requires aftermarket calibration if vehicle is not originally equipped with this gear ratio or a Ford Performance Power Pack Calibration”

so if anyone out there owns a non PP 2015-17 mustang, be prepared to call tuners to see if they can actually correct the issue. During my adventure I only found 2 shops that could do it. West palm beach dyno and Lund. SCT cannot and had them try 20 some times and failed each time.

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