Kick Down Cable on 2000 Pontiac Grand Prix GT

Trans does not have kick down cable computer controled do you mean shift cable?

Well, my Grand Prix shutters at 45mph and stops at 50mph I read somewhere that a guy switched out his kickdown cable and the shuttering stopped, so i was going to try to switch it out too .. if it doesn't have a kickdown cable i suppose i'll have to find another way and research it more, would you happen to know if the shift cable could have anything to do with it?

(i purchased a used grand prix, got it scanned, no codes and checked it out and appears nothing is wrong with it. but i purchased vehicle before looking up well known issues and unfortunatly found out this is one of them .. the shuttering at 45mph....)

That would be problem with lock up torque convertor at 45 - 50 is when it locks so could be TCC solenoid or convertor itself