Lego Sian Gearbox lagging

Hi, we are in the process of building Lego Sian. For some reason the gearbox is lagging when we are trying to switch for the 4th time (where it should turn the left side of the gears). What can be wrong here? Sometimes if im switching it pretty fast it eventually switches, but in other cases it just doesn’t move submitted by /u/AromaticLoan92 [link] [comments]