pulling hard ,dropped power for 10 sec

[ranwel]

2009 6.4 135000 mi pulling long hill with camper not in tow mode/my fault all temps in center, cruse dropped out lost all power all dash lights out and went threw a cycle each one lighting once , spedo dropped to zero, about 10 sec I shifted to tow, power came back up drove another 700 miles, no trouble light yet. was that the failsafe mode? havent had the truck for long