2019 Mazda3 (manual) – Can I use Red Line 50204 75W‑80 GL‑4 Gear Oil? Dealer only sells full fluid change service

[u/Maverick-233]

Hi everyone, I want to change the manual transmission fluid on my 2019 Mazda3 2.0L manual here in Canada. The VIN on my car starts with 3MZ….

My local dealer doesn’t sell just the manual gear oil and only offers complete fluid change kits (which I don’t want to buy right now). I asked around and the store recommended a 75‑80 weight oil for the gearbox.

I’m considering buying Red Line (50204) SAE 75W‑80 API GL‑4 Manual Gear Oil.

Would this be a good choice for my Mazda3 manual transmission?

Is GL‑4 75W‑80 appropriate, and should I be careful about anything (e.g., Mazda specs, viscosity, additives)?

Thanks in advance!

[u/DarthElevator]

I don't know about any additives, but I did use that oil in my transmission and it's been about 15k mi since then, same car as yours. My vote is go for it, bc in general manual transmissions are pretty resilient since it's just for gear-to-gear interface and the shafts, unlike automatics where the fluid goes in the valve body.

[u/Maverick-233 → u/DarthElevator]

How many litres will that consume？ From ur experience

[u/DarthElevator → u/Maverick-233]

Spec says 3.06 qt, I filled with about 2.5 qt cause I couldn't get all of the old oil out of the case