AgingHippie wrote:
I really hope this car isn't turning into a money pit.
Overnight, GOM reading on full normal charge changed from around 74 to around 66, and loud whine developed, seems to be relative to acceleration. Before anybody starts on GOM reliability, I watched it for a few days to see if it was consistent, and it is.
So is it a DU? Is the range reduction related in any way? Should I pay for a diagnostic, or am I in for an argument with Toyota about whether things need to be replaced or not?

Check your coolant levels. If the drive unit bearings are getting really bad then the coolant seals may be leaking too and allow coolant to leak into the drive unit / inverter assembly - very bad.
If the car has a significant noise while driving, go to the dealer and ask them to test drive it, or ask to go for a ride with the service person. Hopefully they would not charge for this. But no one on this forum can predict what your local dealer will charge or whether you will have a rough time with them. If the noise is significant, they should make a recording and submit to Toyota corporate for DU replacement approval.