Welcome to iRV2
Coolant low a couple of gallons is scary , have you checked the cooling system to find your leak ?
How much trans fluid did you need to add ?
What does the trans fluid color look like ?
Have you checked trans for fault codes ?
Is your coach on a Freightliner or Spartan chassis ?
Side radiator or rear radiator ?
I doubt that the engine cooling system has only electric fans , but need more info about the chassis to be of any real help .
EDIT: I see Brett , posted similar questions while I was typing , please add more info about your coach and chassis so we can provide better answers .