It has an expansion valve, and the valve is in the housing in the coach. You'd have to pull the entire plenum chamber to disconnect it from the evaporator. Chances are thie valve is OK, as you did say it was cooling until compressor shutdown. Put in a new drier, evacuate and charge (Don't forget the oil!). Make certain your condensor fan is working too, it'll keep pressures down whilst restrained at red lights...Cal