Tenneco first implemented the lean transactional process ten years ago. One of the key success factors was to ensure that the lean system was sustained within an organization as part of a philosophy of continuous improvement. This has probably been the most challenging part of implementing lean in Tenneco. During the early years of implementation, lean was managed as a top down approach which consisted of: identifyingexecutingand tracking lean projects by the management, a small number of additional people and lean experts.This approach had the advantage of building up critical mass and helped to instill a lean change culture in a reasonable timeframe. But the Tenneco experience showed that even if early results were encouraging, the implementation was not consistent enough to sustain a mindset of continuous improvement.This top down approach needed to be reinforced by a much stronger bottom up approach which consisted of group leaders acting as change agents.Their roles and responsibilities included: designing processes and standardsproblem solvingteaching their peoplesharing the knowledge capturedThis paper describes the lessons learnt by lean change agents in Sales & Engineering and Finance departments at Tenneco.