Private Coachman was a member of the Headquarters and Service Company, 73rd Engineer Combat Battalion, U.S. Army. On 14 October 1952, he was driving a military vehicle near Kung-Dong, North Korea, when it rolled over pinning him underneath.

Coachman was awarded the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.