Shurflo Smartsensor - rebuild or replace?

[Alii]

Any experience rebuilding a Shurflo Smartsensor (micro-processor controlled) fresh water pump? Any info on why Shurflo has discontinued this micro-processor line? My Extreme Smartsensor 4.0 pump has been in nearly-constant 24/7 use for over 10 years. There are no leaks in the system. It has always "burped" every hour or so as the hot water heater has cooled or vented, but over the last week has started to slowly "chug chug chug" after use. Shurflo's customer service has not responded to emails on whether/how I can determine of this new behavior means the valves need to be replaced ($65 part) or the micro-processor is going out (not repairable). Given that Shurflo has abandoned the product line I hate to make even the $65+shipping investment, but replacement pumps are going to cost $175-ish plus $100 international shipping to get something that fits my space. Ideas on how to make the right investment of time and $$?