Will ATF damage my 2009 Subaru Forester manual trans?

I accidently added a small amount of automatic transmission fluid in my manual transmission. Will it damage the transmission? What should I do?

No worries, ATF and trans oil are very similar.
In fact some manual trans specify ATF.


A manual should not be low unless there is a leak so verify that first.

A 75/90 weight gear oil is recommended. There is a difference between a normal manual transmission and the transaxle (proper term) in your Subaru. The Subaru transaxle includes a ring and pinion gear set to power the front axles so therefore the heavier weight oil.

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The ring and pinion may have straight cut gears and not require hypoid gear oil.

I cannot be certain, but it appears that your manual transmission uses ATF. If you have your owners manual, you can check.

Check out Forester forums. Looks like yours needs the “HP” manual fluid.

How much is “a small amount of” ATF?

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