I'm sure it involves some sort of oil or grease or something of that nature.

But that alone doesn't tell me much. There's a pretty wide gulf between a gas motor that needs regular preventive lubricant changes every few thousand miles and other parts, e.g. wheel bearings, that are sealed and lubricated for the life of the part and can be expected to last a couple hundred thousand miles.

"Electric motors need oil changes too" implies something closer to the former than the latter.

I think it's just sealed bearings. The tesla motor is essentially the same as the spindle in a CNC, and those do not require lubrication but do need bearing replacement.