HYDRAULIC TRANSMISSION ASSEMBLY

The present disclosure relates to a hydraulic transmission assembly comprising: a hydraulic transmission for performing speed shifting for the power generated by an engine; a pump shaft connected to the pump; a motor shaft connected to the motor; a sub speed-shift shaft connected to the pump shaft and/or the motor shaft through a plurality of speed-shift gears; a mounting main body having a mounting space for the hydraulic transmission; a speed-shift case having an accommodation space for the sub speed-shift shaft, and coupled to the mounting main body; and a cover part coupled to the mounting main body so as to cover the mounting space, wherein the cover part is coupled to the mounting main body such that at least a portion thereof is accommodated in the mounting space, and provides support power to one side of the sub speed-shift shaft.