Ok…in doubt, the solution would be easy, either ask Bikegang (as far as I know is their connection to ATS pretty good) or just take a look inside via the lubcrication bolt.
ATS themselves linked at their page to the original Schlumpf drive manual;
I’d recommend also to refer to this, much more detailed, real workbench manual.
Here’s an alternative link:
schlumpf.ch / Speed Drive manual engl.pdf
Mentioned “ATS maintenance” document was found here
pacific-cycles.com / ATS Speed Drive maintenance manual.pdf
but sadly nowhere the other two 