How to remove K20 trans dipstick tube?

[Stocker]

It's leaking at the bottom o-ring. Is there any way to access the tube's attachment bolt behind the engine? I can't see it.... barely able to touch it by reaching behind the engine, more or less below the right side valve cover. It's so tight I don't think I can get a wrench in there -- and if I manage to remove it, I'm afraid I won't be able to re-install it.

Am I missing something here? There must be some way to reach that bolt without pulling the engine....