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Discussion Starter #1
Hey Everyone,

I have a 2012 Impala LTZ 3.6L 6-Spd Auto.

At low speeds (20-40mph) sometimes when I let off the gas and then touch the gas I'll feel something like a hesitation and a thump, and I can repeat it over and over.

I first realized this when I was in a funeral procession. We were moving along pretty slow for 20 minutes and I was constantly going on and off the gas.

I took my car to a dealership and they reset the software within the tranny that gets to know how you drive your car and personalizes your driving experience, which didn't fix the problem. The tranny tech essentially didn't give me any other useful feedback and sent me packin. The good news is the stealership didn't charge me - can you believe that?

Anyways - anyone have any thoughts or suggestions based on what I'm experiencing?

Thanks in advance
 

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Don't post often here..But I was just about to post the same exactt issue!

I have a 12' with the 3.6 Its got 92K miles I put around 20K miles on it since January.

Anyways, I am having a "lull" in the gas pedal. When you are lightly giving it gas it seems to stop a second and give it all the power. Not like the 00-11 trannys that would slip..Its more like it is searching for the right throttle to give. If I gun it from a stop, or am passing someone I have all those 305HP.

Anyways, I thought I had bad gas so I tried a couple different stores. Premium did not help me in this case. I had a ton of o2 heater codes in all the locations in banks. p0036 p0056 p0135 p0141 p0161 were the ones in question. car was running great beforehand. I even took it on a 3500 mile round trip this last july.


*edit* I will check my 34MM nuts on my axle. I have not done any work to the wheel bearings or axle and I assume they will be tight. It surly does not feel like something is wrong in the suspension(to say).
 

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Yes! I have a 2016 and same issue for about the last 6 months or so. I have taken it to the dealer twice.. who can it make it duplicate. They basically told me that is what a car does... It doesn't have any codes, so there is nothing wrong with my car. Had the transmission service and still does it. So would love to hear if you figure it out!
 

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My 2016 LT Limited has had the same issue. Only lower speed (under 30MPH) on and off light touch on the gas causes transmission weirdness (shift and gear selection confusion is as good a description as any). Tranny fluid looks good color and level looks fine. Have seen this described as just being how these 6 speed transmissions are programmed on several other threads, but I increasingly find it hard to believe GM really released a car that just happens to shift this weird. Car revs fine in neutral and park, so this does not seem to be an engine issue.

Have not considered the axle nut as a possible solution. May mention that next time I take the car in. On another thread a similarly reported trans shifting problem was fixed via replacing a bad cam shaft actuator (I may be remembering the part name wrong, I am not a mechinic).

I have not yet tried to disconnect the battery to reset the computer, but I have little faith in that as a solution as the computer should surely have learned how I drive by now since I bought the car 16 months ago.

Reported it to the dealer when I took it in for an oil change last Fall and got the standard answer of, "if it isn't setting off an engine light code, then it isn't a problem". Very conveinient until it turns out to be something that could have been easily fixed early on but then costs thousnads of dollars cause the problem was allowed to just keep getting worse.
 

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Oh No!

I just dumped my 2018 Camaro V6, 8 speed for future tranny shudder. The guys on Camaro6 state around 35,000 mile tranny shudders at hwy speeds & Chevy has a temporary fix, flush & a new part to get them thru another 30,000 miles.

I thought I was safe with 2019 Impala with 6 speed tranny. (groan)
 

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Oh No!

I just dumped my 2018 Camaro V6, 8 speed for future tranny shudder. The guys on Camaro6 state around 35,000 mile tranny shudders at hwy speeds & Chevy has a temporary fix, flush & a new part to get them thru another 30,000 miles.

I thought I was safe with 2019 Impala with 6 speed tranny. (groan)
I have not read of any freeway speed transmission issues occurring with any frequency, only the low speed low gear shifting weirdness. I have not read of this issue causing any permanent damage over time. Just that it is a known issue in some (too many) cars and is very annoying, hard to track down and fix.
 

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The hwy speed shudder is on the 8 speed automatic tranny on lots of GM rides. Impala never had 8 speed.

Too bad on the 6 speed. Why is it so difficult to track down?

GM has a service bulletin on the 8 speed issues.
 

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Discussion Starter #11
My 2016 LT Limited has had the same issue. Only lower speed (under 30MPH) on and off light touch on the gas causes transmission weirdness (shift and gear selection confusion is as good a description as any). Tranny fluid looks good color and level looks fine. Have seen this described as just being how these 6 speed transmissions are programmed on several other threads, but I increasingly find it hard to believe GM really released a car that just happens to shift this weird. Car revs fine in neutral and park, so this does not seem to be an engine issue.

Have not considered the axle nut as a possible solution. May mention that next time I take the car in. On another thread a similarly reported trans shifting problem was fixed via replacing a bad cam shaft actuator (I may be remembering the part name wrong, I am not a mechinic).

I have not yet tried to disconnect the battery to reset the computer, but I have little faith in that as a solution as the computer should surely have learned how I drive by now since I bought the car 16 months ago.

Reported it to the dealer when I took it in for an oil change last Fall and got the standard answer of, "if it isn't setting off an engine light code, then it isn't a problem". Very conveinient until it turns out to be something that could have been easily fixed early on but then costs thousnads of dollars cause the problem was allowed to just keep getting worse.
The dealer can reset how a tranny learns your driving style. Dealer did it for free while I had it in for an oil change and tire rotation.
 

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Discussion Starter #13

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I'm honestly not sure. The dealer did both in my case (lubrication and tighten the axle nuts) - not sure exactly which one fixed the issue - but others have reported issues with loose axle nuts, so I assumed that was the primary issue - but I can't be 100% sure. Maybe show the dealership the text from that thread and see if they can check the lubrication since tightening the axle nuts didn't help.

In my case, it was under warranty, but if out of warranty, it's not so easy, because everything you "try" costs $$$.... Or - maybe try another dealer that may be more willing to actually troubleshoot the issues - all dealerships are not created equal.

Wish I could be of more help..
 

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Curious if anything new has developed on this for anyone? I am thinking of taking my 2016 Limited in to the dealer to get new trans fluid and tell them about the stutter/thump thing that happens at low speeds. Trans fluid color isn;t terrible, but couldn't hurt to change it. I have been getting an intermittent P0700 TCM engine code too, not sure if that is related, but again, if the code doesn;t stick around long enough, the dealer says they cant evaluate the problem. I have 2 years of drivetrain warranty left and I would prefer if anything serious developes, that it do so when stil under warranty. I will ask if they can check the lugnuts too, but I got new tires a few months ago and I would hope Sams would have noticed if the hubs were loose.
 
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