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2016 Mazda 3 2.0 6AT Clunky Shifts

296 Views 5 Replies 4 Participants Last post by  WoodinvilleDan
Hi all,
I have a 2016 Mazda 3 2.0 with the 6AT and 80k miles. I bought it at 77k miles.
Shortly after getting the car I noticed the transmission seemed very jerky and like it was uncalibrated.
1-2 gear seems very sluggish, almost like it shifts way too early. If i put it in manual mode and wait to shift out of 1st until 3k rpms, it's smooth as butter. If it shifts on its own, it's very slow to shift, sluggish, and uncomfortable. Even if I'm under heavy acceleration, when the car shifts it's very slow and uncomfortable but in manual mode it shifts way smoother.
2-3 and 4-5 are also very jerky and uncomfortable.
We did an ATF change, 4 quarts came out, it solved part of the 1-2 sluggishness and the 2-3 jerkiness is completely gone.
However, the 4-5 shift almost seems to have gotten worse, or at least, no better. On occasion it almost feels like it shudders.

Is this normal? Or is my trans going out or something? Is there the possibility that bringing it to the dealer and having them reprogram it would fix it?
Also is the generally uncomfy 1-2 shift normal?

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Auto transmissions are fairly reliable and should last more like 200K, as long as they are properly maintained and not abused. Given that you bought the car with 77k on it, you have no way of knowing if your fluid change was the first it ever had, or if the idiot before you beat the car senseless. When you changed the fluid, was the old stuff dark and smelled burnt? Was the pan full of sludge/glitter and did the pan magnet look like a hedgehog? Any of that would be a sign of poor maintenance or abuse, and an indication that the trans might be worn out.

Transmissions do have calibrations that change shifts based on driving style, but you've owned the car long enough that the old calibrations should have "aged out" and been replaced by ones based on your style.

Poor shift quality can also be caused by worn or dirt-clogged shift solenoids. Individual solenoids can be replaced, or the entire solenoid pack can be replaced for reasonable money. This wouldn't be worth doing if there was a lot of sludge in the pan when you did the fluid change though.
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We only did a drain and fill as the car is under the dealer warranty for another 4 years and I don't want to risk voiding it. Fluid was dark brown in color, didn't smell too bad, but had some glitter in it. My dad said it "didn't look bad". I tried doing the transmission relearn procedure but that didn't really change anything. I've been talking in other forums and some people are complaining of having these same issues, so I'm wondering if they're more or less just annoyances with this car now rather than immediate issues. I am considering bringing my car to the dealer and having the TCM reflashed/updated. If all else fails, I hope this trans gives out within the next 4 years so I can get a new one under warranty lol. I can't believe I didn't notice any of these quirks on the test drive though. It seemed to drive and shift perfect, otherwise I wouldn't have bought the car! Thanks for your insight
I suspect the previous owner used the wrong fluid. Your ATF fluid change improved things but remember that drain and fill did not replace all the fluid. Just change it one more time and shifts will improve assuming no permanent damage was done.
I forgot to mention, yes, only 3.8 qts drained out of the 8 qts or so that it holds, so we will be doing another one in a few thousand miles. I don't believe the fluid was ever changed prior to us. My next steps are to do another drain n fill, have the TCM reflashed/updated, and if none of that helps, possibly try and get it warrantied for a new unit. I'm getting responses from other 3 6AT owners in other forums saying that they're experiencing these same quirks too though, so I don't want to assume that my unit is malfunctioning. 🤷‍♂️
Try running through the Transmission re-learning procedure, I do it any time I drain and fill or apply a significantly revamped tune (also I'm supercharged so I put a lot of extra stress on the transmission so I'm extra thorough about this stuff):

*press and hold the brake the entire time
  1. Start the car
  2. put it in neutral
  3. turn it off
  4. Move shifter to the down shift & while holding it, wait 5 seconds, try to start the car (while still holding down shift), it shouldn't start
  5. then slide shifter to neutral again & start the car
  6. then go over to up shift, hold for 5 seconds
  7. then go to down shift, hold for 5 seconds
If you did it correctly the RPM will elevate, once it does let go of the shifter, it will stay elevated for a few seconds.
Once it goes back to normal idle RPM then the transmission reset is done.

Not sure if this will fix your problem, but it's worth a try :)
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