In February 1977, "Ranger" departed Naval Air Station North Island for the Puget Sound Naval Shipyard, Bremerton, Washington, for major overhaul. While in overhaul, she received significant technological upgrades to her command information systems and flight deck gear, and was fitted with Sea Sparrow missile defense systems. Additionally, the main machinery spaces were refitted with more reliable 'General Regulator' forced-balance automatic boiler and combustion-control systems. In March 1978, the overhaul was completed and she began several months of shakedown cruises and sea trials for recertifications.