In the sixties, people began using ATF as a crankcase additive due to the high amounts of detergents found in ATF. At that time "High Detergent" oil was coming onto the scene.
I believe that from that, people began to believe that ATF with its detergents was a cure all cleaning agent. ATF has gone through drastic changes since then. Additionally many great special purpose additives have become available.
ATF is great for use in automatic transmissions. Use special additives for everything else and leave the cure alls for those who still believe the old wives tales.
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in