The Panama Canal was transited on 11 August, and the ship arrived at Norfolk on 16 October 1964 for post-shakedown availability.

The roll, wind, and water parted the tie-downs on cargo staged on the flight deck for the next day's replenishment.

On 16 June 1969 the ship lost a UH-46D helicopter when it crashed during vertical replenishment operations in the harbor of Palma de Mallorca, but the crew was rescued.

On 20 July the ship was awarded the Meritorious Unit Commendation for service to the 6th Fleet during the period 25 April 1965 to 30 September 1969.

After two weeks of refresher training at Guantanamo Bay, she returned to Norfolk for another two-month availability period.

After five weeks of re-loading supplies at Norfolk, the cargo ship returned to the Mediterranean, from 2 October to 10 November 1972, to replenish the AFS that was on station there.

In September 1976, returning from a routine deployment, Sylvania had the honor of transporting the world-famous King Tutankhamun Exhibition to America for the Metropolitan Museum of Art in New York City.

Service Squadron Four consisted of nine logistic support ships assigned the vital mission of providing food, fuel, supplies, repair parts and ammunition to Naval units of the Second and Sixth Fleets.

In this capacity Sylvania assumed the duties of deployed, on-station combat stores ship in early 1980, again from May through November 1981, in 1983 where the ship received the Navy Expeditionary Medal for her participation in Sixth Fleet peacekeeping efforts in Lebanon, again over the Winter of 1983 and early 1984, and in late 1984.

In 1985 Sylvania went through a major overhaul in Norfolk, Virginia in which all of its systems were upgraded and much needed repairs made.

During this period USNS Sirius (T-AFS-8) was upgraded to be able to conduct full operations as a combat stores ship and was included in the Fleet AFS rotation.

This included training operations at Guantanamo Bay Naval Base and ship visits to Ocho Rios, Jamaica, and Nassau, Bahamas.

Typical ports included Málaga, Alicante, Torremolinos, Cartagena, Rota, and Palma, Spain; Toulon and Marseilles, France; Augusta Bay, Sicily and Naples, Italy; the British territory of Gibraltar; Haifa, Israel; Antalya, Turkey; and Piraeus, Greece.