Tenneco ensures vehicles are riding steady without exhausting a lot of smoke. The auto parts maker designs and distributes ride-control equipment (including shock absorbers, struts, and suspensions) under the Monroe brand, and emissions-control systems (catalytic converters, exhaust pipes, and mufflers) under the Walker brand. It also makes Clevite elastomer products (bushings, mounts, and springs) for vibration control in cars and heavy trucks. It supplies both OEMs and aftermarket wholesalers and retailers. Major customers include GM, Ford, Advance Auto Parts, and Uni-Select. Tenneco operates on six continents and is growing its presence in key Asia/Pacific markets.