RE: After-run oil question
Tim C,
The Red Line 75w90 is a gear oil designed for rear ends and some manual transmisions. The funny rotton egg type smell is the different sulphates and phosphates that are extreme pressure additives. How those will react to silicone I am not sure since their standard motor oil does not contain them. The different sulphates will attack yellow metals such as brass and bronze so keep an eye on your rod bushings.
I guess you could not find Red Line motor oil or German Castrol motor oil which would be a good after run.