Automatic issues after tune

[Dadsdreem]

I have a Lund tune in for about 500 miles. At the strip, I ran in drive and toggle in track. 12.4 113mph. The weird thing is if I put the car in drive with sport or track selected or the tranny in Sport on the street, everything is fine EXCEPT when you take your foot off the gas and the car downshifts. It shifts really hard on the last downshift and doesn't feel right. It makes me nervous with the jerking motion from the downshift, so much that I avoid S or T in drive and if I put the tranny in Sport, I paddle shift it so as to avoid the automatic downshifts. If I remove the tune it shifts normally and sounds like downshifting with a manual, which is nice. Spoke to Jon and he said with the SCT, nothing should be changed with the transmission. Anybody have any ideas? Anybody experience this?

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[imjuslazy]

I would talk to Lund. If it doesn't feel right I would avoid replicating what your describing until you figure it out. Don't want the possibility of damaging something.

 

[TheZman]

Try changing it back to stock and see what happens and take it from there..

 

[The Blue Pearl]

Sounds normal to me. I don't have a tune, but I do have the automatic with 3.55 gears. When driving in D and selected with toggle switch to S+ or Track, the shifts are harsher or stronger whatever and the last shift down is harsher still. When driving in D and toggle switch selected to normal- it shifts just that- normal, not as strong or harsh. I believe it's just the normal programming of those maps. S+ and Track are programmed to feel, perform more sporty then when in normal settings. If it makes you feel any better my last car (G37S) when set for DS (drive-sport) mode on a automatic transmission performed very similar. Many complained on that forum of harsh shifts and such, when in reality the car was not broken but instead was just performing as intended. I pretty much keep it in S+ so I'm used to it and honestly the car is just more fun to drive like that. Engine braking is much stronger in S+ as well. Hope that helps.

 

[Dadsdreem]

The Blue Pearl, that's exact how it drove before the tune. Remove the tune and it goes back to normal. Guess I am going to remove the tune and just enjoy it in sport +. But, almost 4 tenths quicker in quarter mile with tune in drive. And in drive it's fine with the tune. And it's fine in sport as long as you use paddles.

 

[The Blue Pearl]

Dadsdreem- 4/10th's is pretty good, maybe just use the tune when at the track? Question off topic though- did your MPG give you a noticeable increase? Did the tune lean the car enough to give you an appreciative increase?

 

[Dadsdreem]

Absolutely did. Very noticeable regular driving around town. I would guess an increase of close to 2 mpg. Going to pull the tune tomorrow. Hate to do it as the car runs so strong in drive. But as I don understand why the weirdness is happening, just gotta do it. Damm

 

[SVTFreak]

If it's fine with the tune in D, why not leave it in and drive in D? That's what I do. Not even sure how my vmp tune acts in Sport mode. Never tried it lol

 

[Dadsdreem]

SVTFreak, I have 3.55's and love to drive it in sport and listen to the downshifts as I slow down. My brake pads are going to last awhile. Lol

 

[mrs2c5s]

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[SVTFreak]

SVTFreak, I have 3.55's and love to drive it in sport and listen to the downshifts as I slow down. My brake pads are going to last awhile. Lol

I have 3.55's also. But will take more power over a gimmicky downshift any day lol.

 

[Dadsdreem]

Power is king! But a change in a parameter that shouldn't be affected, does make you wonder. Guess it's more in the realm of the 6 spd manual where some have grinding and notchiness and others are fine. Anyway, coming out today and gonna be saved for race day.

 

[SVTFreak]

Power is king! But a change in a parameter that shouldn't be affected, does make you wonder. Guess it's more in the realm of the 6 spd manual where some have grinding and notchiness and others are fine. Anyway, coming out today and gonna be saved for race day.

I agree with the parameters that shouldn't have changed. However, that's more than likely due to pressure changes made in the tune and is a by product of parameters that where changed. At least that's what justin and I discussed about some unexpected changes in mine.

 

[Dadsdreem]

SVTFreak What changed in yours?

 

[SVTFreak]

Actually good changes. Mines kick down on accel is instantaneous. Incredible actually. Couple other little
Things but that's the biggest change I wasn't expecting.

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