The 4x4 will not engage when i turn the switch on the dash neither hi or low
when i start the truck the 4x4 high and the 4x4 lo light flashes like it always has but when i turn the switch to 4x4 hi or low no light to indicate it is on and no 4 wheel drive i jacked up the vechile and placed it in gear and fliper the switch (shift on the fly ) and only back wheels turn ....what is wrong ??