SCT Tuned... Rolling to stop, clunk to 1st downshift?

RGVRaptor · Apr 30, 2013

Just noticed this today... This is only the second day I've driven my truck with the new SCT 93 octane performance tune from 5 star tuning and I noticed when on the brake rolling to a stop that the truck shifts down to 1st gear and I'm not sure if it's 3rd to 1st or 2nd to 1st, but it sometimes is rough and I hear a "clunk" as it goes in to 1st gear.

Anyone else experience this? Is it something to worry about? Fix?

Thanks!

banman12 · Apr 30, 2013

The shifts are going to be rough and jerky for a few hundred miles. The PCM has been reprogrammed and now literally has to "relearn" shift points. Nothing to worry about, should clear up soon.

RGVRaptor · Apr 30, 2013

banman12 said:
The shifts are going to be rough and jerky for a few hundred miles. The PCM has been reprogrammed and now literally has to "relearn" shift points. Nothing to worry about, should clear up soon.

Awesome. Thanks for the quick response!

Milez28 · Apr 30, 2013

Umm no, it shouldn't "clunk".. Ive had several tunes and none did that. If you pay good money for a tune it should perform as expected. Call Mike he's good at responding and Im sure he will help you. Its best to talk to him about it since he's experienced in this, if you let it go it "could" cause further problems which I hope doesn't.

FYI - Of the ones I've tried shifted from 3rd to 1st

BIRDMAN · Apr 30, 2013

If you roll through stops a lot the tranny learns to stay in second ...or third for that matter at certain speeds. If you happen to stop rather quickly the trans will abruptly shift to first which can feel like a clunk or a hard down shift. A tune basically erases your adaptive transmission strategy and may act funky for about 100 miles even if you are doing a good mix of driving. If after 100 miles something is still off call mike at 5 star to set you up right.

banman12 · Apr 30, 2013

BIRDMAN said:
If you roll through stops a lot the tranny learns to stay in second ...or third for that matter at certain speeds. If you happen to stop rather quickly the trans will abruptly shift to first which can feel like a clunk or a hard down shift. A tune basically erases your adaptive transmission strategy and may act funky for about 100 miles even if you are doing a good mix of driving. If after 100 miles something is still off call mike at 5 star to set you up right.

Thats what I was getting at. Should have added if it doesnt get better in a 100 miles or so, call Mike.

MTF · May 1, 2013

Fuel Trim cycle is 50 miles and full Transmission cycle is 300 miles.

BIRDMAN · May 1, 2013

After my Texas trip I thought something was wrong with my truck ...similar to what you describe. The nearly 4500 highway miles threw my trans module for a loop and it was shifting really weird for several days. Just cleared up over the weekend...about 400 miles later so that makes sense

MTF · May 1, 2013

All I'm repeating is the quote I got from the SV Team when they used to answer the phone.
So it may take more than 100 miles after a flash or a battery disconnect before things straighten out with the shifting.

These cycles are continuous the PCM is always adapting and setting predictives deep into the wideband to the conditions.

cups · May 1, 2013

MTF said:
Fuel Trim cycle is 50 miles and full Transmission cycle is 300 miles.

What I fuel trim?

SCT Tuned... Rolling to stop, clunk to 1st downshift?

RGVRaptor

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