Studio 4°C is a Japanese based animation studio founded in 1986. Some of their work includes Tekkon Kinkreet, Tweeny Witches, Spriggan, The Animatrix ("Beyond", "A Detective Story", "Kid's Story") and Linkin Park's "Breaking the Habit" music video.
In regards to Transformers, they are currently one of the three studios hired to animate Transformers Animated.
While Studio 4°C is mainly known for doing promotional animation for the series, most prominently the "Mighty Orbots tunnel" sequence seen in the opening credits, it has also animated "special" sequences for episodes, such as transformation and attack stock footage, plus the two DVD-exclusive shorts "Career Day" and "Evel Knievel Jump".