[mholbrook38]

I have done the quart of diesel in an engine just prior to an oil change.....but not on a Porsche. I've done it on some old 100k+ cars that I bought to clean up and turn over. I didn't drive it like that though. Warmed up to temp and idled in the driveway for about 15 minutes or so. Really helps clean them out.

Personally, I would not worry about a 1/4 quart of trans/diff oil into the sump of a car that uses around 10 quarts for an oil change.