1987 420sel white smoke /not shifting
 

Recently on a road trip my fan clutch ended up dying on me.with this my car tempeture hit 110-115 this happen three times(i would stop and let it cool down) but on the 3rd time i was doing 50mph when i tryed to increase in speed the car started banging and wouldnt get past 65. now i replaced the fan clutch and did a tranny tune up and the car ran good for three days, but now i cant get it past 65mph it starts to bang and at start up there is a good amount of white smoke. any clues on why it not shift and why there is white smoke thanks joe

Hmmm... not sure about the banging, but white smoke even after the engine is warm and its warm outside normally signals a blown head gasket. Is the car overheating now?

Is it steam? What does it smell like? Coolant? Oil?

Explain the banging a little more in detail... does it sound like its coming from the engine area?

banging in regards to the car starts to shake when i get to 65mph and it wont shift. the temperture is good now

smoke or steam
 

White smoke can be transmission fluid being sucked into the intake through a faulty vacuum modulator on the transmission and ignited in the cylinders and out the exhaust ,OR as suggested by member 86560SEL ,steam from a blown head gasket .. with the engine warm, hold your hand behind the ehaust pipe while idling , if water droplets form on your hand ,you probably have a blown head gasket ,if transmission fluid forms on your hand and you can smell the transmission fluid then the modulator is faulty ,check the coolant , if oil droplets are present in there then that's another way to tell if the head gasket it blown ,also check the level of the transmission fluid.

Ben