The starter motor for military armored vehicles was known for its reliable quality, with less than one failure reported per year. However, this changed recently when a sudden wave of failures began to occur. The main issue was the “pinion gear teeth” snapping off during operation. When these teeth break, the metal fragments scatter and damage other internal parts, causing expensive repairs and leaving the vehicles unusable. Because it is vital for the military to keep these vehicles ready for action, solving this problem became a top priority. This paper provides a comprehensive investigation into the root causes of these pinion gear failures by examining the entire system from multiple perspectives. First, we conducted a detailed analysis of the individual component, including its material properties and the manufacturing process to identify any inconsistencies. Second, the study evaluates the gear meshing conditions and structural alignment with the mating components to ensure proper power transmission. Furthermore, we analyzed the electrical characteristics of the starter motor, such as current surges during ignition, which could impose excessive stress on the gear teeth. By integrating these findings, this paper discusses the comprehensive process of identifying the failure mechanism and proposes technical improvements to prevent future occurrences.

This study presents a systematic causal analysis of the fuel consumption rate reduction phenomenon observed in mortar-carrier tracked vehicles during driving tests. The investigation focused on identifying the root causes and developing effective improvement measures. Through comprehensive inspections and tests of the chassis and power pack components, along with data analysis, the study identified the damage of the engine flywheel housing gasket and the clogging of the transmission exhaust pump strainer as the main causes of the reduced fuel consumption rate. The causal relationship between the two phenomena was empirically proven using material composition analysis and statistical techniques, enhancing the reliability and validity of the diagnosis. Based on the root cause analysis results, improvements were implemented, including the replacement of the engine gasket and the cleaning of the transmission exhaust pump strainer. The effectiveness of the improvements was quantitatively verified, confirming a significant enhancement in fuel consumption rate and cruising range. By employing a systematic and scientific analysis methodology, this study provides a foundation for improving the reliability and maintenance efficiency of similar weapon systems and power transmission systems in general.