Before the first flight, I noticed an intermittent HW fault display for the GSA Pitch Servo, accompanied by a GMC 305 fault display. I contacted Garmin, though the unit was out of warranty period, I was able to get an exchange for $100 (beats the $750 replacement cost). I opted to have the new unit shipped with a promise to return the original unit afterward because I wanted to deal with this once, not twice.
New unit arrived, so within a short time removed the rear seat back, and rear baggage compartment bulkhead and shelf, then the GSA 28 unit. On the new unit installed the necessary hardware and installed the new unit. Torqued all the connecting nuts and torqued seal.
Powered up the G3X system and no hardware fault displays!