Transmission shifts different

[t89gt]

2015 GT Premium auto with 23000 miles. I installed a JLT cold air intake with a sct x4 tuner. Made a big difference overall but now when driving in D and accelerating hard the transmission shifts slow... almost like it's slipping. In S and sport mode it'll spin the tires a good 4 foot shifting into 2nd. I'm okay with that but if I leave it in sport it no longer rev matches on down shift and when coming to a stop the down shifts are very hard. It down shifts normal in D. My question is has anyone else had this experience and is it a tune problem or transmission on the way out? Thanks in advance.

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[aleccesarenriquez]

Are you using the tune provided by the SCT or did you get an aftermarket tune? If so who's your tuner?

I would bet the transmission issues are tune related. If you want to find out, put your stock airbox back on and load the stock tune (assuming there aren't any other mods on the car). If the trans does the same things, then it's the trans. Otherwise it's the tune.

 

[t89gt]

Yes the tune that came with the sct tuner. I pretty much figured it was tuner related because of how good it shifted in sport and track mode. It's a shame that they make it shift so weak in D normal mode...I expect it to shift smoother but if you get on it hard the shifts are terrible. Guess it's time to find a good tuner. Thanks for the reply.

 

[aleccesarenriquez]

I would recommend a lund tune. I went with a less reputable local tuner first and regretted it. Lund has always been excellent to deal with and their tunes have been perfect for me. PBD is also good, but their shift points in autos are more aggressive from what I’ve heard.

 

[Lo Pony]

You might tryy unplugging and letting the trans relearn if you haven’t already

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