is atransmission flush neccessary

Best thing to do is what the owners manual says and that is to have the fluid and filter replaced and you can find a shop here to do that https://repairpal.com/chrysler-repair-in-green-valley-arizona and check prices for that service here https://repairpal.com/estimator/chrysler/town+%26+country

I had a transmission flush dome for $99.00 Look for another repair shop.