Rear gear change problems, please help

[SlowEldiablo]

Hey everyone, just finished swapping a loaded pumpkin with a Torsen lsd and 3.73 into my Mustang that had a pumpkin with a Trac-lok and 3.31 gears. Took the first test drive and could not tell a bump in the pull of the car, seems like I still have the 3.31 gears still in the car. Also, in gears 4-6 car will not let me pass 4K on the tac, when I put my gas to the floor it just hits a spot with the power band and holds it there. Car is just not acting right at all. I did the same swap on my 2012 GT and the change was night and day. I know a tuner is needed to correct the speedometer change but is the tuner needed to fix the problems I'm having? Like I said, no notice in gear change and I know I left 3.31 to go to 3.73, car will not let me pass 4K RPM while driving, putting the gas pedal to the floor pulls the car so far up the power band then hangs there, will not power through. If anyone has any suggestions, please help.

Thank you,

J
SlowEldiablo

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[SlowEldiablo]

Also, traction control and advanced track was off during the test drive.

 

[Legionofone]

post video

 

[SlowEldiablo]

Wish I could. I don't even know how to post a picture on here. I'm guessing something like photo bucket?

 

[SlowEldiablo]

Plus, I don't think a video of my tac hanging at 4K will show you anymore of what I'm detailing. Pedal to floor tac goes to 4K and stays there.

 

[stang1971]

you prolly need to program the bcm with the correct ratio... it may be seeing too much of a variable from what it needs and thinks something is wrong.

a whipple flare tool or modifying the as built data might fix it.

 

[SlowEldiablo]

you prolly need to program the bcm with the correct ratio... it may be seeing too much of a variable from what it needs and thinks something is wrong.

a whipple flare tool or modifying the as built data might fix it.

Thank you for the info. My buddy told me I'm running in limp mode because my ecu thinks my trans is slipping. Can anyone tell me if Ford can do a reflash or is my only option the Flare tool?

 

[SlowEldiablo]

How does one go in and change the " as built data"?

 

[SWETRID]

Ford procal tool or whipple flare tool only. Dealer cant do it with current tools/software.

 

[SlowEldiablo]

How can I get one and how much do they cost?
Ford pro cal?
The other one?

Thank you for your replies

 

[stang1971]

check in the DYI section... it explains on how to modify as built data....

 

[RomanB]

Can Lund do it if you ask for a retune after a gear swap? Planning on doing a gear swap soon and have the ngauge. Would suck to have to buy another device just to use once after a gear swap.

 

[Evilwill]

Here is the a link to the Whipple one

http://www.lethalperformance.com/whipple-2015-2016-mustang-f150-5-0l-axle-wheel-flare-device.html

Here is a link to the Ford one

http://www.lethalperformance.com/ford-performance-2015-mustang-gt-performance-calibration-manual-transmission.html

 

[2015 Silver GT]

you prolly need to program the bcm with the correct ratio... it may be seeing too much of a variable from what it needs and thinks something is wrong.

a whipple flare tool or modifying the as built data might fix it.

Correct

Thank you for the info. My buddy told me I'm running in limp mode because my ecu thinks my trans is slipping. Can anyone tell me if Ford can do a reflash or is my only option the Flare tool?

Your buddy is correct, your car is in limp mode. Dealer can't help you.

Can Lund do it if you ask for a retune after a gear swap? Planning on doing a gear swap soon and have the ngauge. Would suck to have to buy another device just to use once after a gear swap.

No Lund can't do it since the change needs to be done in the BCM, not the PCM.

 

[MoneyPit#53]

Read up on modifying the "As Built Data". I coded my BCM and adjusted my speedo in a matter of minutes after reading the DIY thread. Saved me from spending a couple hundred on the flare tool. It sounds confusing when you are initially reading up on it but it's actually pretty simple once you get connected and start adjusting the parameters.

-Nick

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