It's in PET. Illustration 398-00R. Part number 902.302.012.55 for ordering the complete gearbox.
The 902/04 and 902/05 that Ed references are there as well.
It's intended for one thing, hill climbs. There's also the 901/51 if you want to talk super short boxes. That's also a hill climb box. 7:31 w/ AA,E,I,M,O.