Heavy-Duty and Off-Road (HDOR) machines have a significant circularity potential. However, the implementation of Circular Economy (CE) in this sector, particularly regarding the End-of-Life (EoL) treatment, is still in its infancy. The present paper proposes a methodology to help a good-producing company initiate its CE transition. It encompasses two main steps: (1) an interview consultation strategy and (2) a classification of the resulting information into the CE building blocks framework, adapted from the Ellen MacArthur Foundation (EMF). The latter aims to identify situations to be improved and CE improvement avenues to be adopted. This methodology, applied to an HDOR manufacturer case study, proves to be highly effective in terms of the scope and complementarity of the CE improvement avenues while being easy to use. In this paper, two recommendations are formulated for improving the heavy machinery sector: proper dismantling and identifying in-use and EoL machines. The authors identify challenges for each of these areas of interest to address to shift towards CE in the heavy machinery sector.