Hello I will help you with your question,
The list price for the pump is $220 and the labor to replace it is 1.2 hours. If you have a flush of the system, fluids and diagnostic time a shop charging $100 per hour the cost could certainly be $435.
If you can let me know exactly what you are being quoted for I can break it down for you but that is pretty close to the correct price.
Please let me know how I can help