Have any of the EV owners on this forum needed to service the vehicle's driveline oil? Have you tried any of these dedicated e-drive oils, or even seen them in your local auto parts store?
Earlier EVs like the Leaf, BMW i3, Tesla S/X and the first-gen Ioniq/Kona/Niro used a conventional internally-dry motor with a coolant jacket. The motors connect to the gear reducer with a normal greased splined coupling.
Most if not all later EVs including the gen-2 Kona/Niro and all other current H/K EVs have migrated to fully integrate the motor and gear reducer to eliminate one bearing between them and the related oil seals. Essentially the motor is allowed to get 'wet' internally with oil and that's used for cooling instead of needing a coolant jacket. The ball-bearings can be open and avoid any issues with using sealed (greased) bearings.
The Bolt has always used this integrated concept and is actually a very good design, IMO. But, it's hardly a new idea as Toyota did this in the gen-4 Prius some 20 years ago.
I've changed my EV's gear oil yearly (six times now) to keep it clean. Primarily that's needed in my case due to a design mistake made by Hyundai where there is no means of effective wear particle sequestration - a subject I covered some time ago in another thread. I think up to 1% of production have failed due to this silly mistake, which as best as I'm aware was never fixed until the gen-2 came out. It's much the same oil change job as any manual transmission - drain and refill until it spills out of the filler opening, just 1 litre required on the Kona.
The now out-of-production gen-1 Kona such as mine and Kia's nearly-identical Niro use a light 70W GL4 gear oil, while pretty much all current EVs use ATF. Of course those are basically the same as far as gear lubrication is concerned and I think the reason for preferring ATF might simply be based on what's stocked by dealers, although the 70W GL4 is also used in Hyundai's DSGs. Since these gear reducers run cool, barely warm to the touch, the thin oils work fine.
There's really nothing high-tech required for EV gear lubrication from what I've seen and I think specialty EV oils are more of a marketing gimmick.
