09/15/2026
327,808 km on the original drive-unit oil — what did the lab find?
There’s been a lot of talk lately from shops recommending Tesla drive-unit oil changes every 100,000 km.
These results are a good example of why I don’t believe a blanket 100,000 km interval is justified.
This 2024 Model Y had 327,808 km on the drive-unit oil before we sent samples from both motors to Blackstone Laboratories.
Front drive unit
* 327,808 km on oil
* Viscosity: still within specification
* Water: 0.0%
* Antifreeze: 0.0%
* Insolubles: 0.0%
* Flashpoint: 425°F
* Elevated iron/nickel, which Blackstone notes may include accumulated break-in wear from running the original oil this long
Rear drive unit
* 327,808 km on oil
* Viscosity: still within specification
* Water: 0.0%
* Antifreeze: 0.0%
* Insolubles: only trace
* Flashpoint: 435°F
* More accumulated wear metal than the front, particularly iron and aluminum
The important part: neither sample showed the oil itself had failed. The viscosity remained in spec, there was no water or coolant contamination, and the oil had held up remarkably well after more than 327,000 km.
The rear motor does have substantially more wear metal, so we’ll sample it again after roughly 50,000 km to establish a trend. One oil analysis is a snapshot; repeated testing tells us much more about actual component wear.
But these results certainly don’t support the idea that Tesla drive-unit oil somehow needs to be routinely dumped every 100,000 km.
Could changing it earlier reduce accumulated wear material? Possibly. Is 100,000 km a necessary universal service interval? These results say no.
This is why at MaintainEV we prefer data over arbitrary maintenance schedules.
327,808 km. Original fluid. Still within viscosity specification.
That’s a pretty impressive result.
