Backlash is controlled in an opposed-piston engine that includes two crankshafts disposed in a parallel, spaced-apart relationship and a gear train coupling the first and second crankshafts, the gear train including a driving gear coupled to the first crankshaft and a split gear assembly engaged with the driving gear to transfer rotation from the driving gear to the split gear assembly. The split gear assembly includes first and second gears, a spring mechanism that acts to angularly offset the first gear relative to the second gear in a first direction, and a one-way clutch mechanism that prevents relative angular movement of the first gear relative to the second gear in a second direction opposite the first direction.