Change differential 3.15 on 3.55.

[GilmourD]

I have yet another concern, because any_key has an automatic transmission. If it's like the automatic Mustang I drove and the transmission computer is stupid, a different final drive might just make the transmission quicker to shift up. Instead of going uphill in a 50 km/h zone in 5th gear, it might go to 6th.

No matter what you do with the hardware, be ready to click the shift paddles and override the software.

After enough days or weeks of telling the transmission what gear you want, it might understand the assignment. In theory.
However, I just found this thread where owners talk about the transmission's "adaptive learning". They're not impressed with it, and they're talking about ways to turn it off:
https://www.mustang6g.com/forums/threads/10r80-adaptive-learning-question.188344/

And that's why you need to use FORScan to tell the computer what gears you have.

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[K4fxd]

When I changed mine to 3.55 from 3.15 I drove the car before doing anything with the software. The car drove fine, shift points were a bit sooner, not really noticeable.

When I got back to the shop I hooked up forscan to change the ratios in the BCM, to my surprise they were already changed to 3.55. The car did it by itself.

I have the same thing happen when I changed my battery from the stock to an optima AGM. I didn't have my laptop with me so I had to wait a week before resetting the battery monitor crap. Again the car had automatically detected and inputted the correct battery information.

These cars are programmed to be a lot smarter than I thought.

Your mileage may vary

 

[ShadesOfBloo]

And that's why you need to use FORScan to tell the computer what gears you have.

So, tell the computer you have a 2.73 rear end, and see if it shifts at higher RPM?

 

[K4fxd]

The lowest gear you can program is 3.13. But even if you did the car will ignore it.

 

[Ogopogo]

I went with the 3:15 instead of the 3:55 on my '22 A10 for lower highway rpm at speed and technically better gas mileage but I doubt that made measurable difference given where the optimal torque curve is. I probably should have stayed with the standard 3:55 for more responsive downshifting at low speeds. I find I will either force a downshift via paddles or stay in Sport at lower speeds.

 

[TonyT930]

Hi. I want change differential 3.15 on 3.55.
What is the difference 3.55 on AT and MT transmission?
And what other change need done, except replacement differential?

If you are planning to go with a power adder later, I would stay with the 3.15 ratio rear especially if you have an auto trans...

 

[80FoxCoupe]

If you are planning to go with a power adder later, I would stay with the 3.15 ratio rear especially if you have an auto trans...

You must know all about his combination to make that determination.

 

[TonyT930]

You must know all about his combination to make that determination.

Well, if you talk to some of the guys that know in the industry, a 3.15 rear with a supercharger for the street makes a great combo. BTW, f off.

 

[80FoxCoupe]

Well, if you talk to some of the guys that know in the industry, a 3.15 rear with a supercharger for the street makes a great combo. BTW, f off.

You are just regurgitating what you hear. Recommending a gear ratio based on nothing, nice. F off? Not a chance, kid. Pull your emotions together and relax.

 

[TeeLew]

You are just regurgitating what you hear. Recommending a gear ratio based on nothing, nice. F off? Not a chance, kid. Pull your emotions together and relax.

You're the one coming off poorly. He stated his logic and it was just a side comment.

 

[80FoxCoupe]

You're the one coming off poorly. He stated his logic and it was just a side comment.

I'm fine with that.

 

[GilmourD]

You're the one coming off poorly. He stated his logic and it was just a side comment.

I dunno... @80FoxCoupe didn't tell anybody to "f off".

 

[80FoxCoupe]

I dunno... @80FoxCoupe didn't tell anybody to "f off".

I just assumed he knew the combo and that was the basis for the recommendation. If that's a poor assumption, I'll take that. But if that's true, the recommendation is worse.

In most cases if a response starts with "Well," and ends with "f off" its safe to say he was unhappy with my assumption.

 

[13GetThere]

What is the standard ratio on of a standard manual Mustang GT? Is it 3.55 or 3.73?

 

[any_key]

What is the standard ratio on of a standard manual Mustang GT? Is it 3.55 or 3.73?

GT 3.55, EcoBoost 3.15

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