Original Mack Military Army Truck Service Manual [T-20-5500, dated December 1942]. This Maintenance Manual covers the Mack Models NR-8 & 9 11 Ton 6 X 4 Cargo Trucks used by the Army. This Manual gives information, troubleshooting, procedures and illustrations to aid in serving these Trucks. It is in good used condition with minor wear and soiling [see photos]. The front cover is missing. Very rare and informative book for the Military Truck Owner or Collector.