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!