Side cover leak

Hey manual trans gurus - I just did a quick rebuild on my 833 OD trans and reinstalled. Works great, except a leak from the side cover. I've not had this issue before on rebuilds, so I'm guessing I installed a regular paper sidecover gasket without sealant, thinking it was a Brewer's gasket that doesn't use sealant. I really don't want to pull the trans again to swap out the side cover gasket. Has anyone successfully replaced a side cover gasket, or just loosened enough to seal it, without pulling the trans?