i use the pwm cooling fan off of a 2009 corvette with a constant temperature controller and it keeps my 96 k1500 z71 with ls2 in it running at 190 in the hot az summer while pulling my camper http://www.dccontrol.com/constant_temperature_controllers.htm
it involves removing trans,removing pan,removing tcc solenoid,taking the pump assembly out,removing the input housing assembly,reverse input drum and band then you will see the yellow clip that holds the output shaft in.