Automatic Transmission "thump"?

TexasChuck

When cold, right out of the garage, sometimes only, I hear and feel a thump when stopping, almost stopped, downshifting into 1st. Anyone have any knowledge on this? 2014.... 15500miles.

Trips

The 7AT is notorious for doing that.

The simple fact they are always looking for the higher gearing to get better gas milage is another annoying thing.

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Wonka2581

I would avoid downshifting into 1st gear.. I also have a 7at and never downshift into 1st. Lowest I'll go is 2nd.

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"I have nothing to offer but blood, toil, tears and sweat""Winston Churchill"

FPenvy

soooooo recently mine has developed the "thump" from 3 to 2.

i drive 99.9% in manual mode. i shift every gear except 2 to 1.....never downshift into 1st. let the car do that on its own.

however sometimes i will also let it downshift from 3 to 2 on its own at low speeds coming to a stop.

now from 3 to 2 if the car does the shift it thumps. BUT when i do the 3 to 2 shift manually on the shifter or paddles there is no thump.

i also got scared that i blew something so i did a tranny flush and it made no difference in the thump EXCEPT the thump only happens when the car is warm and operating temp. cold temp beginning of the drive the 3-2 auto downshift feels normal.

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324whp/258wtq AAM Tuned |F.I. NonRes CF CBE/NonRes TestPipes #373|UpRev Tuner|Akuma Motorsports Intakes|Z1 34 Row Oil Cooler

Wonka2581

Have you taken it to the dealer? Have them look at it?

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"I have nothing to offer but blood, toil, tears and sweat""Winston Churchill"

FPenvy

i let the dealer do the fluid change since i don't have the specific tools to preform that since it's a sealed system and you gotta drain, fill a little, run it, fill a little, run it, etc...

i never ever let the dealership touch my car. well except the warranty steering lock they replaced. obviously couldn't do that on my own lol

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324whp/258wtq AAM Tuned |F.I. NonRes CF CBE/NonRes TestPipes #373|UpRev Tuner|Akuma Motorsports Intakes|Z1 34 Row Oil Cooler

Wonka2581

I hear ya, I would let them check it out..

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"I have nothing to offer but blood, toil, tears and sweat""Winston Churchill"

FPenvy

i think it's fine since it seems like an issue with the ECU downshifting it at the wrong time causing the thump. when i shift the car down into 2nd there's no issue at all.

if something gets worse then maybe i'll have it checked out but not by a dealer.

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324whp/258wtq AAM Tuned |F.I. NonRes CF CBE/NonRes TestPipes #373|UpRev Tuner|Akuma Motorsports Intakes|Z1 34 Row Oil Cooler

Wonka2581

Do you have a tune?

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"I have nothing to offer but blood, toil, tears and sweat""Winston Churchill"

FPenvy

yes the ECU and TCM are both tuned but that was a few years back so i feel like that's not the issue.

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324whp/258wtq AAM Tuned |F.I. NonRes CF CBE/NonRes TestPipes #373|UpRev Tuner|Akuma Motorsports Intakes|Z1 34 Row Oil Cooler

Wonka2581

Hmm well keep us posted..

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"I have nothing to offer but blood, toil, tears and sweat""Winston Churchill"

FPenvy

wont be an update unless it eventually blows up lol

even after the thump i went to the drag strip. thing rips perfectly still with no issue.

like i said the only time it's concerning is when the car shifts itself from 3 to 2 and the car is at operating temp.

hence why i did a fluid change thinking the fluid just went thin. i thought it would help but still there which makes me wonder if they actually changed it or just charged me. being a dealership not actually preforming the work but charging is a completely possible.

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324whp/258wtq AAM Tuned |F.I. NonRes CF CBE/NonRes TestPipes #373|UpRev Tuner|Akuma Motorsports Intakes|Z1 34 Row Oil Cooler

danelonson

My 2012 AT does the "thump" from 2nd to 1st sometimes especially when warm. Sometimes it's really bad, the first time it happened to me I thought I got rear ended from the strong jolt it caused. Don't know if it's normal but mine did it since day 1.