Underlying and undiscovered technical debt (TD) that burdens the system and makes future changes more costly or impossible poses significant risks to mechatronic systems. Multi-disciplinary collaboration and cooperation lead to interdisciplinary interfaces and new life cycle phases that cause greater ripple effects to the TD distribution. When quantifying TD contagiousness in interdisciplinary engineering, only a few metrics, methods, or tools prove applicable. In this work, we propose a method containing two key metrics to quantify TD contagiousness across product life cycles and disciplines. Furthermore, we suggest a matrix multiplication method to quantify the adverse impact on each discipline and the system. By applying the methods to the data of three comparable companies in the industrial automation domain, the results enable us to measure and prioritize the TD incidents’ contagiousness. This method provides a first step towards the systematic quantification of TD in the interdisciplinary environment and provides metrics to compare systems based on objective factors.