Locking a torque converter is stupid. It destroys converters and will take out the trans once the torque convert clutch wears out. Ford rangers have this very problem (inc commodore owners who lock TCC)
I've been doing this for years and never had an issue. Get the right converter built to do this and you will never have problems. The problem is people try and do this stuff with converters that are not built to handle that additional stress and they have problems and blame the component with no understanding of why. This is a factory transmission calibration and this is how they have calibrated it from the manufacturer. Please don't compare a Ford Ranger converter to a Isuzu, two very different parts. The Ford Ranger converter is junk compared to the Isuzu.
