As69rc on a 2014 3500 4th is like neutral

I have 2014 3500 with the Aisin transmission 110000 miles it shifts fine and will go threw 1st 2nd and 3rd but when it shifts into 4th it goes into what seems like a neutral and doesn’t down shift or go into limp mode until I make a complete stop it goes into limp mode turning the truck off and back on takes it out of limp mode checked all wiring it all looks good anybody out there have any idea what it could be also getting a code p2757 for the Tcc solenoid also which one is it I have an extra valve body to steal one from I couldn’t find a problem with them when I checked them out