Maybe he doesn't need the gearbox, but he needs a diff and something that brings the power to the axles.
Regards, Markus
BTW: nice and very interesting project. At the moment we do have a 996 EV conversion over here in Germany. Conversion is done. Car drives, but some detail work left:
Umrüstung / Entwicklung Powertrain Porsche 911 (996) auf Elektroantrieb - Elektro Porsche - PFF - unabhängiges Porsche Magazin & Forum