READ THE TECH MANUAL! Seriously, it's in there!
The -10 TM is a simple to read operators manual. I just don't understand why people won't read it. (know it all or I wont read it because I was told to attitudes, kill people every day).
Obviously the forestry dept is not trained sufficiently! Please take a minute and contact the supervisor there and offer to share the TM information with them.
Always(when parked) leave your stop cable out and your transmission in neutral.
If you really want to get down to it, my November 1977 dated copy of TM 9-2320-211-10 (Operators Manual for Truck 5-Ton, 6X6, M39 Series) states that following on page 2-53 under "Stopping the truck and engine":
"c. After the truck had come to a complete stop, move the gearshift lever (3) into neutral position.
d.
Set handbrake (4) and release clutch pedal (7) and brake pedal (6). Do not let truck coast backwards.
e. Allow a hot engine to cool off (idle 5 minutes prior to shutdown) to avoid serious damage.
CAUTION
THE DIESEL AND MULTIFUEL ENGINE SHUTOFF CONTROL KNOB MUST REMAIN IN THE
STOP POSITION WHEN TRUCK IS NOT BEING OPERATED TO PREVENT ACCIDENTAL STARTING OF ENGINE.
f. Pull out engine shutoff control knob on diesel and multifuel engines (antidiesel control on gasoline engines).
g. Place all switches on the OFF position.
h.
PLACE TRANSMISSION SHIFT LEVER (3) IN R (REVERSE) POSITION AFTER ENGINE HAS STOPPED IN CASE THE HANDBRAKE (4) DOES NOT HOLD."