Ryan, in order to be sure that we give you the best possible opinions, it is necessary to have the serial numbers, and the engine model.
In the forklift world, we don't go by "year of manufacture" much, as they don't build as many machines each year, and keep designs for a much longer time, but some manufacturers have different engine options for each series of truck, your GLC030 Yale can have either a Mazda or GM engine, and depending on the serial number series, can possible have a few different fuel systems, so we will need to know the fuel type too.
now, first a smiley so everyone knows that the rest is non-serious ;-)
you have my apologies for your having left the Automotive world and are now stuck in the forklift world, (it seem to me to be incredibly difficult to get out of the forklift world, once you are fully into the forklift world).