Preddy , Thanks for input.
Above could be possible but still does not answer questions why GV works again okay after oil/filter cleaning.

GV Techkies said Volts issue but why only happening after long driving months and is gone after new oil.
In my point of view it's like loose band in 727 but then in GV unit.
Slip causes material to make oil dirty and clogs filter and GV switches of.