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Can I use ATF in a Manual Transmission?

I am planning to change the transmission fluid and filter in my wife’s manual Mazda 3. Is it ok to use ATF?

What does the owner’s manual say?

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I have never heard of a Mazda with a manual transmission having a filter

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I know for a fact that some of GM’s manual transmissions used ATF, back in the '80s. So, maybe Mazda has a similar practice… or maybe not.

Rather than asking random strangers via the internet, wouldn’t it be wiser to use the same transmission lubricant that is specified in the Mazda Owner’s Manual?

My 1984 GMC S-15 with the 5-speed manual used Dexron-3. I think in some tranny’s they’re still using Dexron 3/4.

Use the correct tranny fluid. Read the owners manual or call the Mazda dealer. Putting in the wrong fluid could be disastrous.

I don’t think your manual transmission has a filter, and regardless, most manual transmissions take some kind of gear oil.

The easiest way to handle this is to go to a Mazda dealership and buy the manual transmission oil recommended for your car. They will know which one you need and how much you’ll need to buy. You’ll spend a little extra for their brand than you would at an auto parts store, but you’ll have the information you need to buy a cheaper brand next time, and manual transmission oil doesn’t need to be changed very often.

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My owner’s manual specifies Mobil 1 0-40 so who knows? Well the answer is the manufacturer knows!

What I don’t know is why anyone would even consider the risk of damaging a $3,000 transmission at a 100,000 mile fluid change by using anything else?

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My 1979 Celica’s service manual 5 speed specifies
80w90 GL4 gear oil. I had to scour the web years ago, to buy a 35 pound bucket of the right (GL4) oil, as I heard that GL5 could damage the brass synchro rings of the tranny.

Don’t know if that is actually true, but I’d hate to be in a position of saying “If only I had bought the other oil”.
I have enough oil left to last me until they plant me in the ground (or at least by that time I’ll be 95, and not in the mood to be driving a '79 Celica!

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You were right in getting GL4 instead of GL5. GL5 contains sulfur which can react with brass. Had the same problem with my 98 Pathfinder. GL4 ONLY. GL5 was fine for the differentials, but not the tranny.

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