I'm planning a drain and fill for my transmission fluid and filter on my 2020 CX-5 soon, vehicle at 93K km = 56K miles. This will be the first change to my knowledge. I'm the 2nd owner. I have this same question, gasket or RTV?

I don't mind mucking around with cleaning surfaces and using RTV if it is superior, but I would prefer not to. Also, seems recommendations are to allow up to 24 hours for RTV to cure before refilling the fluid. Suddenly a 30-45 minute task becomes 24 hours. No thanks. I would certainly appreciate comments on gasket v RTV, and if gasket, material and brand recommendations?

Thanks. And nice tip on the Castrol Transmax. Although since this is my first change, I don't know what fluid type is currently in it. Seems buying a different kind from the present fluid would lead to a miss-match if not all fluid gets drained.

 

Gasket whenever it’s available. Maybe that is a personal preference based on over 4 decades not having one leak, and can’t say the same about Sealer/RTV only . I can also state that unless extreme circumstances I only use gaskets for customer services.

Mixing any transmission or engine oil as long as the brands meet the manufacturer basic specifications have no negative effects mixing different brands .

I won’t state what I use in my Skyactiv transmission but it not 100% Castrol. But I would say 90% .

 

Suggestion for brand / part number of after-market gasket? Looking at some filter + gasket kits on Amazon but brand is vague. I'm in Canada, NAPA here does not source either.

Thanks.

 

Any gasket will work fine as long as it is for your pan on your Mazda. I use the inexpensive gaskets on amazon myself. It's all about how you tighten down the gasket in a series of small steps in use a cross-tightening pattern like a wheel nut.
As for filter I have looked at name brand and generic and taken many apart to look at the filtering quality ....My conclusion I don't think really have changed much as compared to an oil filter for quality. LOL

You Must Verify your Mazdas application
this is the last one I have used twice now on my Mazda.

 

This is definitely one of the most critical parts that you can't forget!

 

2020 CX-5, 6 speed automatic, 2.5 L SKYACTIVE, no turbo

Since my last inquiry post, today was finally change the ATF and filter day due to the arrival of cooperative weather.

• Vehicle at 94,300 KMs = 56,600 miles
• I believe first ATF change for the vehicle, I ignore the fallacy of “lifetime” fluids; when I simply inquired about Mazda ATF and filter pricing, I was firmly told by a Mazda dealership “You never need to change the filter or the fluid, I can’t even price the filter, it’s not in our system.”

Observations of the project:

• OEM fluid was cooked black, drained 4.2 litres = 4.4 quarts leaving about 3.5 L = 3.7 quarts remaining in system.
• Inspecting pan, it is in excellent condition, no corrosion or blemishes.
• All 16 of the pan bolts loosened nicely and were removed with ease; there’s often “that one bolt” isn’t there? but, thankfully not in this case.
• 15 of the 16 bolts were in pristine silver condition, I was pleasantly surprised; a single bolt was blackened with some rust and gunk and I was concerned, but it did remove easily.
• The most challenging part was separating the pan from the transmission due to the Mazda OEM sealant, no gasket here; careful and patient prying with nylon pry tools worked.
• I concentrated on the right front corner of the pan as it has the most access. Once it separated, I could wedge in another nylon shim. Sliding another nylon tool along the length, and suddenly the whole pan released.
• Collector magnet had the thickest layer of particle gunk I’ve ever seen.
• Interior filter, which is not just a “metal strainer” as some say, has a fabric insert, was clearly visible and loaded with filtered particulate.
• Original plan was to utilize a rubber gasket instead of sealant. Alas, the gasket kits ordered from Amazon were incompatible. Filters were fine, perfect fit, but the gaskets were not. Almost half the bolt holes were misaligned. A couple by half inch. So, I used Permtatex Red gasket maker, high temp and does not degrade with fluids.
• Utilizing nylon scrapers and a fine brass wire “toothbrush”, all residual OEM sealant was successfully removed from the pan and transmission housing. Took about 40 minutes. Again, patience here not gouge the pan or transmission surface.
• Applied the red Permatex on the pan and reinstalled with bolts finger tight.
• Waited one hour per instructions before torquing to 7.5 ft lb - easy with hand strength. Easy here, I believe the bolts are aluminum. Gradual tightening in a repeated star pattern until all snugged.
• Now the waiting. Permatex instructions are to wait 24 hours for full sealant cure before refilling and operating. This is the part I wanted to avoid by using a rubber gasket. Not meant to be.
• Refilled 4.2 L = 4.4 quarts of Castrol Transmax ATF, spec compatible with Mazda FZ and I bought for 60% less cost.
• I plan two more drain and fills in about 1000 km = 600 miles each to purge more OEM ATF.
• Future fluid changes will be around 60K kms = 36K miles.

pan removed

old OEM sealant on pan

burnt OEM fluid

magnet gunk

filthy filter

clean magnet

fresh RTV sealant

 

My brother-in-law's father-in-law who just passed away, had a Subaru Forrester with over 300K on it.
He never changed any fluids in it at all only added them.
An oil change to him was a filter change and adding just enough oil after to make-up what he lost changing the filter.
It was still running fairly well. My brother-in-law changed all the fluids and put new spark plugs in and still operates as required (optimal...who knows for 300K).
A friends sister did the same with her Honda Civic and got 250K before she sold it.
I've had blown engines and transmissions with vehicles with less than 50K on them and all maintenance and fluids changed religiously.
Go figure...

 

GREAT write up and detail to the picture observation and conclusions!