Hey everyone,


I have a 2019 Acura TLX V6 AWD Advance, and I’ve experienced most of the well-known 9-speed transmission issues—most of which were fixed with two TCM software updates. However, I’m still looking for a solution to finally resolve the last remaining issue.


Initially, when I bought my car used in September 2024 (with low mileage—about 20k miles/32k km), I encountered several widely known transmission problems:

• The car would slip into neutral during hard and aggressive acceleration, which was particularly dangerous on highways. I’d have to brake to a full stop, turn off the car, and restart it just to force it into Park and make it driveable again.
• There was about a 3-second delay when selecting and shifting between gears (for example, from Park to Drive or Reverse, vice versa). During that delay, the car remained in a quasi-neutral state where pressing the gas had no effect.
• The gear shifts at low speeds were hard and jerky, with the transmission holding high RPMs as if it were in Sport Plus mode.

Less than a week after purchasing the car—and after doing extensive research on forums—I visited my local dealership. They informed me that two TCM updates were available (at my own cost, of course[img alt=""]data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7[/img]. After having both updates completed within a week after my purchase back in September 2024, the issues with Neutral gear slipping, the delay in gear engagement, and the hard, jerky low-speed shifts were completely resolved.


However, I’ve since noticed a persistent clunk and slight jerk specifically when the car shifts from third to fourth gear during steady, low-speed acceleration. If I accelerate aggressively, the effect is minimal, but it remains noticeable otherwise. This can be felt both in automatic and manual shift modes. If you experience the same issue, try downshifting the gear to third, and upshifting it to fourth, you should be able to feel that clunk-like shift.


Since my two TCM updates were completed in September 2024, I’m curious if anyone knows of any subsequent TCM updates or further releases addressing this issue??I’d prefer not to pay for another diagnostic scan at the dealership unless there’s a confirmed update available. Is there a way to check the latest TCM software version code with Acura?


Any insights, advice, or similar experiences you would like to share would be greatly appreciated!

Let's spread this thread together to help more 9-speed TLX owners who might be experiencing the same problems!

 

Has the trans fluid been changed on your car at all?

Last trans TSB about update was 2020: https://www.urvi.net/forumfiles/SB/B20-015.PDF

you can find all the tsb's here:
https://acurazine.com/forums/5g-tlx-...letins-968410/

 

I don't think the trans fluid has been changed yet since the car was only about 20,000 miles / 32,000 kms when I bought it. I m assuming the previous owner never changed it because it didnt reach the maintenance schedule. Now the odometer is about 26,000 miles / 42,000 kms, and the car is about 5+ years old since it's a 2019 model, should I get one done at the dealership? I heard that it's quite pricy to perform a change. Should I do a trans fluid change or flush? I also don't feel like by changing the fluid would resolve the specific 4th gear clunk-like shifting issue though, what do you think?

 

I don't think it would hurt the trans but I'm not sure if it will 100% fix the issue... the new fluid may soften the clunkiness that you are experiencing. Never flush the transmissions on Honda/Acura's, it's always a drain and refill only. Most honda dealers offer a cheaper ATF change on the ZF 9spd in the TLX than acura.

Out of curiosity, are you sure it's the 3->4 shift that's rough and not the 4->5?

From my understanding, the shift for 3-4 uses the same internals (friction and clutch material) as the lower gears (1->2, 2-3, and 3->4), it's the 4->5 that needs the dog clutches to disengage and engage in the ZF 9spd trans that is used in the TLX that takes longer and can be a bit more abrupt/clunky.

 

Thanks, I did see some successful stories from a few other posters about a transmission change (prob due to the restored viscosity of the fluid) smoothing out the clunkiness, so I will prob do one soon. Good idea to have it changed at Honda dealers if they offer cheaper ATF changes, are you sure the fluid they use is the same as the one from Acura dealers? Or is it basically the same fluid just labeled as OEM Honda instead of OEM Acura?

I am 100% sure that the shift is always from the 3rd to 4th, I have tested out multiple times using manual shift mode, where I would just downshift it to 3rd and upshift to 4th to replicate that unsmooth/clunky/jerky and sluggish shift. The unsmooth upshift can be felt passing from the bottom of the car floor, and is audible to be heard as well, depending on occasion, sometimes it's clunky and sluggish enough that the whole car would sort of act as if it braked slightly because your whole body would get pushed forward a bit from the inertial force when that happens (imagine you slightly and quickly tapped on the brake while driving). All other gears seem smooth for me, 4th to 5th, no issue at all, which is a plus for my case I guess as I know a lot of people still experience issues with other gears.

 

I couldn't find much information on what should control the 3rd to 4th shift other than this doc from Sonnax (sell some good stuff to make the trans more robust:
https://d2q1ebiag300ih.cloudfront.ne...=1651087765299

Page 10 shows no 3-4 as a symptom for Clutch E system - (2nd from top on left side).




Page 5 has some more info: