I know converters slip below the stall speed on auto transmissions (they have to otherwise cars couldn't idle in gear, and major bog would persist). At stall speed, there is supposed to be no slipping between the engine and trans. But what about above the stall speed, does the converter slip then??? Thanks.

 

on drag racing rpm formulas i've seen , you can figure in 300- 400 rpm on the big end of the track. the only way you don't get any slipping is with a lockup torque converter

 

and even the tcc slips by at least 2%