For the United States, there were a total of three Voltrons. Voltron I of the Near Universe was the Vehicle Force. Voltron III of the Far Universe was the "Lion Force." Voltron II, from the Middle Universe, featured three humanoid robots that combined into one multi-armed fighter. Toys based on Voltron II were sold in the US, but the show was not. In Japan, there was only Lion Voltron. The other two combiner robots were from other Japanese mecha shows: Dairugger (Voltron 1), and Albegas (Voltron 2).
Pidge, who was a member of the Lion Voltron Force, had a brother named Chip, who was part of the Vehicle Voltron Force. However, the two Japanese inspirations for the show, Hyakujû-ô Goraion (1981) and Kikô Kantai dairugger XV (1982) are not related, up to and including these characters. This is also why the antagonists in both series were known as belonging to one race, the Drules, in the American version; while "Kikô Kantai dairugger XV encountered them only after they began a planet search, the Vehicle Voltron Force were always watching out for them (and the Far Universe inhabitants were mentioned as being a part of their empire in the first season).
The first season of Voltron was not a straight dub from the Japanese anime series Hyakujû-ô Goraion (1981) (neither was the second from Kikô Kantai dairugger XV (1982)) due to American broadcast standards - "living" beings were never killed on-screen; mechanical creatures, however, were fair game. One of the most noticeable differences involves the character Sven. In the Japanese version, this character died after battling the enemy's witch after six appearances. In the American version, he was seriously injured and left to heal, and returns near the end of the season. In the Japanese version, this was his brother at the end of the series. Similarly (and more obviously), Commander Zabbar was two characters; in the Japanese the character was killed and replaced by another commander. The third season was originally intended to be an adaptation of Kosoku Denjin Albegas (1983). But World Event Productions decided instead to join with Toei Animation and make new episodes based on Hyakujû-ô Goraion (1981). The second season adaptation of Kikô Kantai dairugger XV (1982) was not as popular as the first season "Goraion" episodes.
Neil Ross tried some different boys' voices to use as Pidge, but these were rejected. Thinking the character he had been shown an image of was a one-shot character rather than a recurring one, he finally provided the squawking voice as a gag, and the crew decided to use it.
In the First Lion season, Keith said "Form arms and body" in the Voltron formation, but "Form arms and torso" in episode 20, Pidge's Home Planet, but later said "torso" in the second Lion season. Jeff, always said "torso" in the Voltron formation in the Vehicle series.