I am inquiring the group here about the best way to clean the bell housing on my Cougar. Since it is off the car and on the ground I figured it would be easy to do. I was thinking about non chlorinated brake cleaner.
I had a transmission that looked like an old, burnt cast iron skillet when it was actually aluminum. Here is what worked for me:
The Purple power cleaner from Autozone as a 50/50 mix with water will melt off most grease and grime. If you can’t submerge the bell housing, just keep spraying it down to keep it wet for a day or so. Then a pressure washer or a scrub brush and garden hose will work wonders.
I use Gunk Engine Shampoo for stuff like this, along with a parts cleaning brush to scrub it in where the gunk is heavy. Hose it off and repeat if necessary. Works well.