But it would void the warranty!
Since you gave hints instead of clickable links, I've really fallen down the rabbit hole.
'DIY electric car forum for the MGR' found
Highlander Hybrid and Prius motors - DIY Electric Car Forums which is our own OP - e*clipse. It kind of tapers off in Jan 2014, with a detailed description of the drive flange I need to adapt to.
But 'Ivan's garage forum rewinding to lower voltage' led among others, to
RX400H transaxle - The Australian Electric Vehicle Asn - Page 1. This is really interesting thread for two pages before it goes off the rails. Especially
this post from Novgorod with info on the Tamagawa resolver.
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Oil cooling is a fallback position. I'd like to see some data logged first. As far as rewinding goes, I'll point to
#post443275. Maybe Toyota's engineers know what they're doing. Like using a variable DC-DC inverter so a low loads the 280v is used directly but at highly loads the voltage rises, which reduces switching losses (it says here...)