Also "900-series" trucks are the 915, 916, 917, 918, 919 and 920 trucks, which are basically militarized commercial trucks (TM 9-2320-273-10).
They use the NTC-400 Cummins, the Caterpillar D-7155 16-speed automatic, Rockwell axles 4.44:1 (915) and 6.17:1 (for the others).
Transfer case is...