Limp Mode 1776 Chrysler

I have a 2004 Chrysler Concorde Limited with 68k on it. It has a code 1776. Issue: Check engine light will come on, a mile later the car will shift into low when it is down shifting while slowing. I can pull over, shut car off and turn it back on to get it out of low. The car now has been to two dealers for this problem. The first replaced the valve body and solenoid. Didn't fix problem. So I went to second dealer. They did the exact same thing, plus added a new computer... Took car, after ten minutes light came on again. After a mile or so while slowing car shifted into low and stayed there until I shut down. NOW they want to replace the tranny? I'm sick of these guessing games and cost... ANYONE have a solution, because clearly these so called technicians DON"T :) Thanks in advance.