2011 FORD F-450 SD Steering Problems

TRUCK WAS PULLING MY 16K 5TH WHEEL CAMPER OVER THE PASSES BETWEEN MONTANA AND IDAHO IN TOW HAUL MODE UP AND DOWN. THESE ARE ONLY 4,200 FOOT PASSES BUT STEEP. USUALLY IN 6TH GEAR BUT SOMETIMES 4TH GOING 50-55; OIL TEMPS SHOW AS 220 TO 239 THEN THE BIG FAN KICKS IN TO COOL IT. ON ONE OF THE SMALLER PASSES, SHORTLY AFTER I CRESTED THE HILL THE TRUCK SHARPLY DOWN SHIFTED (I THINK IT SKIPPED 4TH AND WENT INTO 3RD. IMMEDIATELY THEREAFTER THE "CHECK ENGINE" LIGHT CAME ON, ?TOOL? EMBLEM SHOWED ON DASH, "LOW POWER" NOTICE SHOWED ON DASH, AND I BARELY HAD TIME TO GET HALFWAY OFF THE ROAD BEFORE I LOST POWER STEERING AND BRAKES. THIS COULD HAVE BEEN A HORRIFIC DISASTER ON JUST ABOUT ANY OTHER INTERSTATE HIGHWAY LOCATION, LET ALONE TWO LANE ROADS THAT WE HAVE BEEN WITH OUR TRUCK/TRAILER. AS IT WAS, IT WAS...