Tail Shaft Leak - was "Is this gasket available? A904 Extension Housing Snap Ring Cover"

The small one under the plate that gives access to the snap ring for removing the extension housing has many different names online when people talk about it. Should be just a small flat gasket with two holes like the one in this Amazon link below. I thought I found this listed in other places but do not see it right now. Try visiting a local transmission repair shop and see if they can sell one individually. Otherwise, maybe try one of the Mopar specific shops like A&A and transmission, Andrews Racing Transmission, or Cope Racing Transmissions.

https://www.amazon.com/Output-Shaft-Bearing-Gasket-12305J/dp/B0CGSW7XGT?tag=fabo03-20