On Side 7, only one unit, the RX-75-4 Guntank, survived the Zeon Zaku attack. This remaining prototype made its way to the Pegasus-class assault cruiser White Base. The Guntank design fought alongside the RX-77-2 Guncannon and the RX-78-2 Gundam, but it was easily outclassed due to the close-range nature of warfare under Minovsky interference. However, after the death of the Guntank pilot Ryu Jose, the mobile suit was upgraded to be used by a single pilot in the canopy-style cockpit, and continued to be piloted by Hayato Kobayashi. The RX-75-4 Guntank was finally decommissioned at the Federation's General Headquarters at Jaburo, South America in November UC 0079 having served admirably in its short service.
In the original Mobile Suit Gundam anime TV series, the RX-75-4 Guntank was not decommissioned at Jaburo but continued service on board the White Base until it was destroyed at the Zeon space fortress A Baoa Qu. The discrepancy between the two versions of events exists because the Guntank was seen more as a 'super robot' genre mecha than the 'real robot' genre mecha that the series was aiming for. The movie version of events is considered more canonical, as it reflects the latest version of Tomino's vision.
The RX-75-4 Guntank first appear in Mobile Suit Gundam, design by Kunio Okawara.
The RX-75 Guntank was given a new look to make it more realistic in the "origin" manga, changes from the animated 1979 guntank include a shorter torso, and the open area between the driver's cockpit and the gunner's cockpit suggests that this Guntank does not utilize the FF-X7 Core Fighter used by the original.
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