Abstract: A transmission assembly for a mechanically controllable valve train. The transmission assembly includes a gas exchange valve, a coupling element, a slotted guide module comprising slotted guide tracks, mounting members, a camshaft, cam following roller elements, at least two transmission elements, and a valve stroke adjustment device. Each transmission element is directly or indirectly in an operative connection with one gas exchange valve via the coupling element. The transmission elements are mounted via the mounting members in the slotted guide tracks. Each transmission element is in an operative connection with the camshaft via the cam following roller elements. The valve stroke adjustment device sets different maximum strokes of a gas exchange valve. The mounting members and the cam following roller elements are mounted on a rotary axis. Each of the cam following roller elements has two mounting members assigned thereto to increase a rigidity of the rotary axis.