Spare Engine: Icing on the Cake

So after calling a few places, found that only Bryant Transmission is willing to run the cases through their hot tank (soap and water only, no chemicals).

Decided to take another look at the cases, with an eye toward prepping them for the hot tank.  But I realized I'd never really tried to clean the black sludge, having always just assumed it would take extraordinary measures to get it off.

So after scraping out the thickest stuff with a pick, and realizing it basically had the consistency of cake icing, I just tried spraying it with WD40 and wiping it off.  Lo and behold, it cleaned right up.  So now it's not so much a matter of how to get it off, as it is about how to reach all the nooks and crannies.

Whatever I can reach with my fingers can be wiped off with a shop paper towel.  I just got some "sponge on a stick" things from the paint store and will see if those can reach the crevices.