Was watching this guy Rainman Ray on you tube do a tranny service, and he pulls out this really neat handled funnel with flexible hose. Looks great for buried fill tubes. I went searching to see if I could find it and came across this site for fluid management. As always I post up links for stuff I'd like to get. Might have to find a couple of these funnels.
https://www.hopkinsmfg.com/catalog/catalog_flotool.pdf