If yours is the same as my 2004 33' they are Firestone Airide Rear Air Spring P/N W01-358-8184. I bought them from SD Truck Springs little under $200 ea.
https://www.sdtrucksprings.com/index...d=W01-358-8184
You have to remove the top frame bracket on new bag as Country Coach welded it to the frame. And I would get new air fittings to replace the old ones. Don't use plastic fittings use brass about $10 ea.
It's a lot easier to access if tires are off but could be done with them on.