Musnad Ahmad 30:2734

Hajjaj narrated to us, he said: Ibn Abi Dhi'b narrated to us, from Salih, the freed slave of al-Taw'amah, from Abu Hurayrah, who said: The Messenger of Allah, peace and blessings of Allah be upon him, said: "Whoever washes a dead person, let him perform ghusl (full ritual bath), and whoever carries him, let him perform wudu (ablution)."