Automatic transmmissions have breathers too, and extending them is the same process as for any other transmission/diff.
It's a long time since I messed with a Jimny auto, but from memory it's on the rear of the case above the tail shaft - you can see it in the photo below.

I haven't paid a lot of attention to how they are set up on a Jimny, but it's not uncommon for them to already have an extended brother on them up to the back of the engine block. This is the case for the AW-4 in the Vitara.