Actually, an old friend of mine says he used
pepper (about a pound, ground pepper of course) in his trucks radiator to stop a bad leak. This was before "radiator stop leak" was readily available. He keeps joking that with the prices of everything going up the pound of pepper now costs more then the stop leak does
He says "but hey, it worked!"
Fabian: Wikipedia doesn't say much about ATF, from a random forum "most ATF and synthetic motor oils are made from the same group III base stock oil".
Here is a link to a thread I found, guys discussing running 50 to 100% ATF as fuel in diesel trucks. Seems to have no ill effects, but don't forget they are using it as
fuel, not for crankcase lubrication as it would be used in a 2 stroke.
http://www.dieseltruckresource.com/dev/do-you-run-atf-t195072.html?t=195072