Is there a narration from Imam Ahmad in which he contradicted the consensus?

Consensus (Ijma') is a valid proof. Imam Ahmad was very strict regarding anomalous opinions, stating: "Beware of speaking on an issue for which you have no guiding Imam." Interpreting Imam Ahmad's statements in a way that corroborates each other is preferable to interpreting them as contradictory, especially if the other opinion is an innovation. Furthermore, Ahmad's adherence to the Sunnah (definition) and narrations is well-established through continuous transmission. What has been attributed to him regarding dissenting from the consensus of the Salaf, such as praying in a usurped house, is not accurate, for what is meant is not an explicit, transmitted consensus. Al-Sam'ani denied the occurrence of such a consensus. Therefore, Imam Ahmad did not contradict an explicit, transmitted consensus, but rather what others merely presumed to be a consensus. The texts of the Messenger of Allah, peace and blessings be upon him, were too exalted in Imam Ahmad's view to be superseded by a presumed consensus, especially one whose lack of a known dissenter is not guaranteed. Imam Ahmad was among the most knowledgeable people regarding the methodologies of the Salaf. Thus, he might have differed from most of his contemporaries on certain issues while aligning with the sayings of the Companions and the Tabi'un. He might have erred on some issues, may Allah have mercy on him, but there is no issue for which a sound consensus has been established that contradicts his view.