I'm new to Mazda and picked one up a 2018 CX5 off dealer, that has 127,000 miles...
First thing i did was to replace oil n filter and then cabin filter which i feel it was original it was so plugged up. And today i removed the spark plugs which looked original, also and changed them.
So now my question is the transmission fluid n filter. -
As the other day while using cruise control it down shifted to get up a hill but after the hill it wouldn't upshift and was turning over 3,000 RPM, and then i had to slow down and then speed up again to get it to shift correctly .
So im thinking its beyond just draining and fill , and that i need to remove pan and also replace filter.
So what type of fluid and how many quarts may it take 5 or 6 ?.



Here is a few pics of old plugs and cabin filter.

 

The transmission sounds like you are more likely not understanding the shift programming. Your shift description may or may not be normal,
You leaving the cruise control likely caused the shifting delay . It would have shifted when you were no longer under load and changed to a slightly less throttle position and after the transmission shifted you could reactivate the cruise control.

However to be sure….

My suggestion is to have a qualified Transmission service shop check it out.

let them do a basic pan and filter replacement because the investment will give the the opportunity to look at things you would know were questionable.

But if you feel like you must get 6 quarts to make sure you’re will have enough and use a gasket for the pan not sealer alone . Any brand filter will due and I recommend Castrol ATF

 

If the cabin filter was that dirty I record a HVAC system cleaning. Easy 30 bucks DIY friendly procedure
And the boots and springs on the spark plugs should have been replaced with your new spark plugs

 

I would be somewhat concerned if I bought a car with that level of neglect in its servicing. They just drove it until they were tired of it. How often did it even get oil changes? I would change every possible fluid you can.

 

Welcome to my world of 1 out about my guess 20 vehicles that come into our service shop.

This is not uncommon nationwide.
Most of it stems around cost of service. It is a balance of people not realizing the downfall to not keeping up on servicing and that a vehicle is an ongoing expense and investment.

 

Hindsight for Carls2018 now, but those items should've been checked before purchase.
Dirty cabin filter and old plugs would be a good indication of the lack of service maintenance.
Mazda recommends cabin filter change every 2 years though I inspect mine 2x a year and change it at least once, plug change every 75,000 miles.
Would be best to get all your fluids changed including engine, transmission, coolant and brake.

As Callisto said a percentage of people never maintain their vehicles and this likely one of them which generally doesn't bode well for longevity, but you never know.

 

A female attorney at a law office I worked at back in the 80's bought a brand new Honda Civic hatch as her daily driver. She never took it in for service and three years later, it just stopped running with 120,000 miles on it. The mechanic said that the engine was full of sludge and there was not enough of that left to keep the engine from seizing from lack of oil. Most of her trips were local, but she would drive down the block to go to a restaurant while the rest of us walked.

Of course, in her mine, the Honda was a poor car.

 

Im a retired Chrysler tech, and where they used RTV on transmission pan it was best to use when servicing , as what was avalible then was cork crappy gaskets and they always came back leaking.
Im picking up 6 quarts of Mazda fluid tomorrow at a good price and gonna sevice it . So what type of gasket is available, as i will not use cork type.

 

Very rarely are cork even used anymore for engines. The gasket material is now made up of compound material that seals very well without the rtv mess .
I only really ever use rtv more for hold a gasket in position but in very small amount.
Don’t forget a new drain plug washer.
When you drop the pan As you are a tech then you should know what to look .


If you look at my personal thread I detail that transmission service on my Mazda a few times.

 

https://www.mazdaforum.com/forum/sea...archid=1442658

You will need to either thumb threw it or use advance search to find all the transmission info.