A precise control of the launcher in MLRS(Multiple Launcher Rocket System) is important for a mission completion. During the field operation of the MLRS, a friction noise was heard in the elevation clutch that controls the launcher. It was confirmed that unsteady friction between friction plates and clutch plates has caused the noise in the clutch. Conducting the analysis of drive mechnism in the clutch, there was a possibility of the unsteady friction because of moderated spring constant. Therefore, after performing experiments on the elevation clutch varied with spring constant, it was determined the proper spring constant. Finally, an improvement on the spring constant in the elevation clutch is expected in the future by utilizing the result of this study.