2007 Dodge Caliber transmission

The transmission sensor lights up., then the cars starts to slow down. I have to pull over, wait about 20-30 mins to cool off. I took it to the dealer, check codes, pay lots of $$$ nothing. They change a cable that was attached to the transmission, pay more $$$…nothing. They say there’s nothing wrong, well they don’t have to pull over every half hour to let the tranny cool off. Any one know anything about this problem?