The front motor is geared at 9.34:1.
It used to be in the owners manual but now it's gone. Strange. It's still listed on Edmunds and other sites:
2015 Tesla Model S P85D Road Test Specs | Edmunds.com
"Final-drive ratio (x:1) 9.34 (front); 9.73 (rear)"
I have never seen 9.34 in the manual or in the service catalog. Tesla only list 9.73:1 for both :/
Do you have a copy of the manual when 9.34 was listed?