Howdy everyone? My 2016 CX-9 with 88k mls on it started doing some weird shifting today. When acceleraing normally, the car shifts as it should from 1st to 2nd and 3rd gear, however when upshifting from 3rd, the transmission drops back into 2nd gear for a second, rpms go up, before it then shifts into 4th. All other shifts are normal.
I also tried shifting manually and it does the same thing. Any ideas?

 

Ok so my thoughts ... the transmission has never had a pan fluid and filter service? If so what miles. If not get one done ASAP it will give a lot of information as to the condition of the transmission by what is in the pan and also how the valve body looks.
The gear cluster in an automatic is often described referring to shifting like a manual transmission. It's not. So, the shifting issue being described may be valve body related that control the mechanical end of the transmission shifting. It does not describe at this point as computer control related.

 

Thanks for your reply. Transmission fluid has never been flushed, is recommended at 90k mls I believe. I will drop the car for diagnostics today and will report back.
Does the shop usually drop the pan for a transmission flush? Or do they just replace the fluid from the top (like an oil change on the car when you pump out the oil - which BTW I would never do :-) )?

 

Unfortunately, that service schedule has already been shown to be less than the best for a MAZDA automatic transmission. It complies with the warranty service but can in many cases cause issues in the transmission.
I would only advise simply getting a fluid pan and filter service. Have them wipe the valve body to see if there is a varnish if so then you can decide if a full service is warranted. That is a fluid replacement ONLY with a TRANSMISSION SERVICE MACHING DO NOT HAVE IT DONE ANYOTHER WAY> If the shop does not have that equipment find one that does. DO NOT have the service of a full fluid replacement done without a Profession Transmission service machine. LOL I think I have WARNED enough about that?

You can also and maybe you should pull a sample of the fluid and send it in to have it analyzed. This will absolutely tell you the current condition of the fluid as well anything that is ion the fluid of concern.
Transmission | Blackstone Laboratories (blackstone-labs.com)

 

Beware of certain shops with the fluid transfer machine that use only Dexron ATF plus an additive to make it so-called correct for any car. Ain't so. You want to use either the Mazda fluid or one specifically listed as suitable for our cars.

 

Sorta a good point but I would only recommend that a service be done at an ASE Certified shop that displays the sign and has current certified Technicians. Ask them if they don't display the sign we like to brag about our ASE certifications.

Never herd or read this of this? If it is a Professional Transmission service machine (they cost from upward several hundred to the better once several thousand dollars) that you do not first fill the tank revisor with the proper Transmission fluid for the vehicle the service is intended for.

I post OFTEN to only do any full-service fluid replacement with a shop that has that type of equipment. I DO NOT RECOMEND a DIY fluid replacement most because none I have seen on the internet work as thought by the posters of those DIY method. There is a reason why the service machine uses variable fluid pressure when doing the full fluid service replacement!

 

Not Iffy-Lube's ATF transfer machine?

 

You seem to have left the "J" out
Ya you and a few other that rip on a successfully business. Jiffy Lube service currently 20 million customers each year. You mostly only read like everything else in the world of forum negative experiences.

As for the jiffy lube there are some that have Professional quality Transmission service equipment. Jiffy Lubes are a franchise so there are many that are owned and operated by experienced and trained in the automotive industry as automotive technicians and mechanics.

They have had their fair share of issues as company overall but never the less they have gotten through many of them, and they are slowly moving back up as a go-to for fast oil change service and other minor services.

 

Didn't want to miss telling the end of my story. On the morning when I drove to drop the car off, everything was BACK TO NORMAL! No issues at all! Transmission shifted perfectly. Anyway I dropped the car off and (no surprise) they didn't find anything, there was an update for the TCM which they installed. The car seems to shift a little smoother now but that may be the placebo effect. Anyways I paid for an 1 hour of labor and that's it.
I also asked about transmission service and was told that "I don't need to do it". The Skyactive engine apparently has no recommended fluid changes at all is what they told me. Fluid supposedly is good for a lifetime! Anyways, I left it for now but will for sure do some more research on that.
Thanks for everyone's input and I am glad I got out cheaply especially this time of year!

 

Good to read...

But...
Transmission fluid and filter service on even the new Skyactiv engine with automatic transmissions needs to be done at no later than 50k miles sooner (starting at 15k miles or even sooner than that) and then again at least at 15K mile service schedules.
*The fluid will not last the lifetime in clean condition which a defined lifetime is 100k miles.
*Lots of transmission oil analysis that supports this.
In your case I would recommend to have the pan dropped and cleaned, filter replaced and 4-5 quarts of new fluid. .