2015 Mustang GT Automatic Shift Point Woes

Hi folks,
I have a 2015 Mustang GT / Automatic. It has 3.15 gears in the rear. I drive it daily to work. This is the first automatic Mustang I own and I have some questions.

As you know there are a few driving modes which change the personality of the car. Mostly, I use Normal and there is Sport and Sport Plus. I spend most time in Normal mode since its a daily driver but I am not really happy with the shift points in the 5.0 GT. in Normal Mode. It always goes for 6th gear, even around town. At 40MPH the engine is cranking around 1200 RPM, which is annoying when bumping slight throttle to accelerate. Is feels “boggy” unless I push the accelerator to kick down, which is too much. I say it feels like my grandfathers Oldsmobile!!. At 50 MPH cruising I oftentimes switch to manual mode and hold it in 5th which is more responsive. I added a Sprint Booster V3 for improved throttle response, which helps. But it doesn't stop the fact that the tranny searches for 6th at low speeds no matter what. When I go to Sport or Sport + Mode it wakes up a bit, but holds in lower gears too long and downshifts aggressively when coming to a stop. Its cool, but annoying when driving to/from work. Sometimes in Sport mode when I’m cruising down the highway at 65 it downshifts into 5th for really no reason, which I don't like.

I rent the Ecoboost l4 Mustangs on business trips and I really like those shift points. Its very responsive and shifts perfectly for zipping around town and on the the highway. These cars have same transmissions and likely the 3.15’s, as well. The car feels much more “drivable"

I been on the forums and spoke to Ford Performance about some options. Here is what they are and what was said:

- Can I put the Ecoboost tune it the 5.0 GT so it will shift the same?. Ford performance said not possible based on many different factors between the 5.0 and the turbocharged l4.

- Change the rear axle ratio from 3.15 to 3.55 or 3.73. I cannot see how the shift points would change, but higher RPMs would get the engine RPM up a bit which may make it more responsive. But the 3.15's are probably OK for the transmission gearing, especially 1st and 2nd which are pretty tall. And on long trips I really like the MPG I get with the 3.15s especially when I have cruise control set for 3 hours!. I don't really want to compromise that. Plus, does it really address the issue?

- Consider a custom tune. This could adjust shift points I think, but I’m not interested in hard shift points or aggressive downshifts like I see in Sport or Sport + modes. Im not looking for a drag strip tune or crisp, wheel chirping shifts. What I am only looking for is more responsive and better shift points and a better mapping for my daily drives, in Normal Mode. (like the Ecoboost Mustang). I don't want to keep shifting to manual mode. or pushing the pedal for downshifts just to have it go right back to 6th when I’m going for a gallon of milk!!

- Does a tuner from SCT/Bama help? Are there canned tunes or will these guys be able to help address the issue, which Im sure other Mustang enthusiasts have encountered. This ay I would get a tuner and be able to have more options for performance tunes as desired. Or are these tunes too generic to help.

Im trying to get an idea where to best spend the money to meet the objective.

Thanks folks.

I think EB is tuned so it does not cause LSPI damaging the engine.

I'd get a custom tune and stay away from Bama. Go for something from Lund or team Beefcake or one of the other vendors on here. They can be tweeked to your liking too.

AED has the shifts dialed in

It's crazy expensive to swap from 3.15's to 3.55's. I've considered it but I don't think my car is held back by 3.15's, I have traction issues as it is.

Ford has programmed these cars to hunt the highest possible gear for fuel economy and on a high reving engine like the Coyote, it feels sluggish around town in D. I'd go for a tune from a reputable tuner and I think you will be much happier. I've rode in a Lund tuned car and the shifts are insane at WOT. Over the top in my opinion. I'm going with AED this summer but Livernois and Palm Beach Dyno seem to have good auto tunes as well.

PP2 would be a great option if your concerned with the warranty.

You can't put the EB tune in a 5.0 for many many reasons, but that shouldn't stop you from copying the shiftpoints of the EB into a 5.0 tune.

As others said, you need to get a tune that will customize your shiftpoints to your liking...and a good starting point would be to mimick the EB shift points and go from there.

Best solution is to put it in sport mode and shift it yourself with the paddles, that’s what I do 99% of the time.

Even when tuned, the transmission characteristics are still similar...D mode wants to put you in 6th gear around 40mph with light throttle or sport mode revs downshifts and holds gears too long at light throttle.

get a Lund tune and ask for "soft shifts" i love how it shifts now (15 GT).

The stock tune will upshift as much as possible to save gas, and will feel laggy and not so much like a v8. Get a tune, and it will drive way way better, and wont be too aggressive.

For instance my Lund tune now in D is excellent. Quick down shifts when i need it, soft fully driveable shifts in D. When i put it into sport mode, with the paddles, i can skrrt 2nd gear and chirp third on WOT. Was probably the single best thing i have done for a daily performance car.

FYI i had the ford performance stage 2 (which gets a tune as well) and the shifts were a little better, but it was still laggy in D and wasnt how i would like it. I really respect Lund and their customer service, they really worked with me on the tunes to get it just to how I wanted it.

BlownOne said:

Best solution is to put it in sport mode and shift it yourself with the paddles, that’s what I do 99% of the time.

Even when tuned, the transmission characteristics are still similar...D mode wants to put you in 6th gear around 40mph with light throttle or sport mode revs downshifts and holds gears too long at light throttle.

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I dont have this issue with the Lund tune.

Lund tune is great. I really like it in all modes. In addition to Sport mode and using the paddles to manually shift, you can use the paddles to downshift in 'D' when needed without creating a lot of kick-down. It will automatically upshift after acceleration.