Why wont your yard king snow blower change gears?

There could be many causes and here are a few that I can think of at the moment: * Bent, damaged, or misadjusted shift linkage. * Inadequate lubrication at all of the pivot points in the linkage between the operating lever or handle and the transmission. * Rusted detent ball inside the transmission. * Not enough lubrication inside the transmission. I'm suspecting that there probably are a few more, but these are all I can think of at this time. most snow blower dont have trannys. its driven disc system, there is a rubber wheel that moves back & forth against a metal disc. the metal disc runs off the belt & the rubber wheel drives the wheels, the speed is varied by how close the wheel is to the center of the disc, its a dry system. if you dont find the problem in the linkage, often the rubber wheels pops out of the forks it moves back & forth in, if the disc is worn at all its a good idea to replace while you have it off. if it comes out again the fork may be bent. have fun!