73chargerman

my son has a 99 dakota, 4x4 5.2ltr, with 44re automatic. the truck has 175,00 on the motor and the tranny has about 70,000 miles. the tranny shifts in and out of O/D every 20 seconds or so, shifting back down into 3rd and then into O/D again. the tranny temp light comes on and goes off as it shifts. in the past years i have replaced the shift solenoid, and the governor pressure solenoid. when this problem appeared i replaced the O/D solenoid and the temp sensor. they are only serviced as an assembly. i also replaced the ets (engine temp sensor) as this was the only code stored in the pcm. it currently has no codes stored, historical, or pending codes. i have no idea where to go next... any help would be appreciated. thanks G.Meyer