The Detroit Diesel Series 40 is an inline, six cylinder, 7.6 or 8.7 litre diesel engine. It has been used in transit buses, specialty commercial vehicles, and as a generator. The engine known as the Series 40 is actually the International/Navistar DT engine. The 7.6 litre Series 40E is the DT-466E and 8.7 litre Series 40E is the DT-530E. Detroit Diesel and Navistar signed a distribution agreement in October 1997. Detroit Diesel only sold the 8.7 liter series 40E engine to coach/bus manufacters and discontinued the product in 2004.