Like said...and here's some to ad for the heck of it...if you've ever watched videos of trucks or cars racing the 1/8 or 1/4 mile...you may have noticed that the versions with automatics are reving above idle...lets say for instance that you hear the engine spinning at 3000 rpm but the truck or car isn't moving...that is transmission stall...a 3000 rpm stall is for higher rpm engines...ones that reach peak torque at higher RPM's...for instance...a 3000 RPM stall on a stock cylinder would be totally wrong..why you ask? Because the stock 6 cylinder chevy peaks torque between the RPM's of 1600-2200....so a 1500 RPM stall would be much better....but for an engine that peaks torque at 4000 rpm like a big block...then 3000 rpm stall is fine. To sum up...stall is the amount of slippage allowed before the transmission "locks" so to speak.