Initially plans were for a rapid acceptance into service, but problems with the locomotives being slightly out of loading gauge caused delays.

At the time of the M551's acceptance into service production in 1966, the United States Army no longer used the heavy, medium, and light tank classifications.

In April the following year, two months after the ship's belated acceptance into service due to teething troubles, Dowling embarked Sydney for Australia with two squadrons of fighters aboard.