, you need to lock up the torque converter or risk burning the trans up. the way it was explained to me is, the torque converter generates heats when not locked up. from there, the fluid is sent to the trans cooler and back to the trans to lubricate its internals. if the lock up is not used, the fluid is not sufficiently cooled and, over time, will destroy the trans.
Isn't that the way every pre-lockup AT works?
Ran a 200C for 6 years and over 40000 miles with no functioning lockup...which is more than many TH200s lasted when new.