Today I tried to address my transmission problem (slipping in 1st and 2nd). I hoped it was just low fluid, so warmed it up and opened the fill bolt.
Had to add 1.5 quarts before some started coming out of the fill hole, and what spilled out was a black murky mess (see photo). So I knew that was a bad sign - probably clutches got burned up.

Sure enough backed it out of the driveway afterwards, and 1st gear is still all but useless, and I can hear it just slipping and spinning. I don't have the tools to do anything more than fluid changes, so will need to bring it to a shop that can hopefully rebuild.