Although the last new episode aired in the U.S. in 1987, through its spin-offs the Transformers series continued in Japan until 1990. As of 2013, a Transformers series has been in production for 26 of the last 30 years, often numerous ones at the same time.
In season 1, there were 24 autobots [Optimus Prime, Skyfire, Bluestreak, Hound, Ironhide, Jazz, Mirage, Prowl, Ratchet, Sideswipe, Sunstreaker, Trailbreaker, Wheeljack, Cliffjumper, Gears, Huffer, Windcharger, Brawn, Bumblebee, Grimlock, Slag, Snarl, Sludge, Swoop] and 22 decepticons [Megatron, Soundwave - with 4 casseticons, Reflector x 3, Skywarp, Starscream, Thundercracker, Shockwave, Bonecrusher, Hook, Mixmaster, Long Haul, Scavenger, Scrapper, Bombshell, Kickback, Shrapnel]. In season 2, there were 15 new Autobots [Perceptor, Omega Supreme, Beachcomber, Cosmos, Powerglide, Seaspray, Warpath, Blaster, Grapple, Hoist, Inferno, Red Alert, Skids, Smokescreen, Tracks] and 5 new Decepticons [Dirge, Ramjet, Thrust, Blitzwing, Astrotrain]. In the end of Season 2, 10 new Autobots (The Aerialbots and the Protectobots) and 10 new Decepticons were introduced (The Stunticons and the Combaticons).
When Optimus Prime transforms into robot mode, his trailer moves backward and disappears from sight, while only the cab becomes the robot body; when he transforms into vehicle mode, his body becomes the cab, and the trailer reappears from nowhere and connects itself to the cab. Many fans wondered what exactly happens to the trailer during the transformations, but no explanation has been ever given. (Although, it has been thought that Roller comes out of the trailer at these times and wheels Primes trailer away. It can be confirmed with Hasbro's masterpiece figures, Roller can attach to Primes trailer.)
Another connection to the GI Joe cartoon, also based on a Hasbro/Marvel comic is the character of Marissa Faireborn. In one episode, Marissa speaks with her father, voiced by Bill Ratner (in his only appearance in the Transformers cartoon), who also provided the voice for Flint, whose real name is Dashiell Faireborn on the GI Joe cartoon. So Marissa is the GI Joe, Flint's, daughter, presumably with Lady Jaye.
Episode scriptwriter Donald F. Glut claimed in 2001 that he didn't like working on the show, because the schedules were so rushed that sometimes he had to write scripts under a day, and in some cases, he could only submit the first draft to the animation agency. Later, in 2007 he said he actually hated the cartoon, and only worked on it for the money. Even so, he wrote some of the most famous episodes, and was the second most prolific writer.
In issue 146 of the original Transformers Marvel Comic series, the Dinobot Grimlock writes in response to a letter from the fans that the comics depicted the "true" events of the Transformers mythos, whereas the cartoon series was purely a work of fiction.
Because both Bluestreak and Prowl changed into Datsun sports cars and had similar helmets with "devil's horn" crowns, the animators tried to avoid confusion between the two by removing Prowl's shoulder-mounted rocket launchers which were apart of the toy Prowl. However, occasionally animators would accidentally color Prowl grey like Bluestreak.
Skyfire's cartoon appearance is drastically different than his toys. The reason for this is that Jetfire was, at the time, a "borrowed" mould of a previously release toy from the rival company Bandai. To avoid unnecessary legalities, the Skyfire cartoon sketches were heavily modified (The Transformers: Fire in the Sky (1984)).
The Autobot Skyfire (who first appears in season one's The Transformers: Fire in the Sky (1984)) was based on a Transformers toy named Jetfire, who in turn was a copy of the design of the SDF Macross/Robotech VF-1S Valkyrie jet/robot (Hasbro had bought the rights to produce copies of the Takatoku/Matsushiro/Bandai Valkyrie toy as part of the Transformers line some months before Robotech aired in the US). The character's name and design were changed to avoid any legal issues.
While there were some GI JOE/Transformer crossovers in the comic books there were no crossover episodes between the two shows until the third season when a character voiced by Christopher Collins named Snake makes an appearance as an arms dealer wearing a trench coat, hat and a mirrored mask over his face. At the end of the episode he screams, "COBRA!" the battle cry for Cobra Commander
In Marvel Comics, Sparkplug has a son named Buster, Spike's younger brother. Buster was the first Witwicky depicted in fiction, and filled a similar role in the early comics that Spike filled in the animated series. According to the comics, Spike was away at college for the first few years of the war between the Autobots and Decepticons on Earth. When Buster was kidnapped by the Decepticons, Spike returned home and rescued his brother.
The evil group of animal-based Transformers that eventually became the Predacons originally started out as a benevolent group of Autobots, called "Anibots". Razorclaw's original name was to be Simba, Headstrong's was Clump, Tantrum's Thump, Divebomb was Shriek, while Rampage was Pardo, and would have turned into a leopard, rather than a tiger. Their combined form would have been called "Dragon Beast", as opposed to Predaking. They would have first appeared in The Transformers: The Movie (1986) to fight Devastator, but after several script rewrites, during which the Anibots became the Predacons, they had been written out of the story, and debuted later in the cartoon's third season.
Although many characters that wore face-plates instead of mouths (such as Optimus Prime and Soundwave) have made this feature iconic, they were originally intended to have true mouths underneath those plates in various related media. The Marvel comics, for example, gave Soundwave a generic human face for a few issues, and Optimus Prime himself can be seen without his face-mask in one of the early story books. Some later re-imaginings of these characters opted to continue depicting them with mouths. Many other characters, like Bumblebee or Windcharger, were based on toys that also had a face-plates but received normal mouths for the cartoon show.
Only toys that came from molds made by the toy company Takara got characters in this show. Toys from molds that were produced by other companies never appeared. Roadbuster, Whirl, Barrage, Chop Shop, Venom, and Ransack were all based off of molds from a competing toy company, Bandai, so they never appear in the cartoon.
Bob Budiansky, who was given the task of naming the toys supplied to him by Hasbro in order to help create the story for the Transformers line, gave his characters alternate names to accommodate them as a form of choice. In the case of Starscream who was a silver jet in vehicle mode, one of the alternate names given to his character by Budiansky was 'The Silver Snake'. Though this name was never used, but remained in Budiansky's original notes, it is interesting to note that the character of Starscream in the original G1 series was voiced by comedian voice actor Chris Latta. In addition, Chris voiced the character of Cobra Commander in another popular cartoon of the time 'G.i.Joe' The voice Chris used for both characters were identical and were the two characters Chris was most remembered for. In addition, to being part of a "Snake" named group as its leader, the character of Cobra Commander was seen often wearing an iconic "Silver" face plate that concealed his identity that was revealed in the 1986 'G.i. Joe The Movie' as being partly snake like in form due to a science accident, hence making him somewhat of a 'Silver Snake' in his appearance.
In The Transformers: More Than Meets the Eye: Part 1 (1984), an orange Autobot in the form of a truck crane appears briefly to haul Hound up for repairs. This Autobots only appears in this scene, never speaks or transforms to robot mode, and is referred to as "Hauler" by Cliffjumper. Apparently, this was an early version of the Autobot called Grapple, who later appears in season two.
All of the other characters introduced in the movie were given new voice actors. The Constructicon Mixmaster (a character voiced by Frank Welker) falls into lava in episode The Transformers: Heavy Metal War (1984). In his next appearance (The Transformers: City of Steel (1985)), he acts quite insane. Later, in season 3, Galvatron (Frank Welker) lands in lava and goes insane as a result (episodes 3.01, 3.02, 3.03, 3.04 and 3.05 "Five Faces of Darkness Part 1-5".
The Decepticon jet Thundercracker never uses his sonic powers in the series (his toy tech specs do say he has them, and he uses them in Marvel Comics). However, in The Transformers: Heavy Metal War (1984), Megatron, using the combined powers of all the Decepticons, does use them.
Omega Supreme was originally going to be called "Fortress Maximus". Although his name was changed, the name Fortress Maximus is later given to a character who first appears in the series-ending, episode 4.01, 4.02 and 4.03 "The Rebirth Part 1-3".
Season 5 did not feature any new episodes. It consisted of 15 episodes from the previous seasons and The Transformers: The Movie (1986) (separated to five episodes). New opening and closing footage were added to each episode, which portrayed Powermaster Optimus Prime meeting regularly with a live-action human named Tommy Kennedy to tell him old Transformers stories.
At Frank Welker's request, Megatron's lines were always saved for the end of each recording session, since the character's raspy voice put a strain on Welker's throat and affected his ability to perform any of the other roles he had in the series.
Sparkplug Witwicky's real first name is not revealed in the TV series. In Marvel Comics, sometimes he is called William, and sometimes Irving. The character based upon him in the 2007 live action film, Transformers (2007), played by Kevin Dunn, is named Ron.
At the time of season one, Spike Witwicky is about 14 years old. His love interest, Carly (introduced in season 2), is about a year older than him. Generally speaking, the Autobots have blue eyes, and the Decepticons have red. There are exceptions, though. Some include: Swindle (purple), Thrust (yellow), and Motormaster (purple). The Autobot called Broadside's character model was totally overhauled halfway during season 3, so it would more closely resemble his toy.
The original idea behind Ratchet was "the best tool guy or girl". Since early on in the production, there was a rule against female robots, Ratchet became a male. A similar case happened in Transformers: Animated (2007), since they originally envisioned the main Autobot cast with a female medic, who eventually became the male Ratchet. Later, in the aforementioned show's third season, a female medic finally appeared for a short time, named Red Alert.
Although Buzzsaw was part of the first line of Transformer toys, he did not appear until the second season episode The Transformers: Atlantis, Arise! (1985). He appeared only in four episodes of the whole series - unlike Laserbeak, who appeared very frequently. The reason for this contrast was that Buzzsaw's toy was only available packaged with Soundwave, and hence did not need to be advertised via the show.
When the Transformers toy-line was first released in Europe, the leader of the Autobots was changed from Optimus Prime to Jetfire, who was actually a character of less importance. This was because they didn't know at the time whether figures of Optimus Prime will be sold. After the Optimus Prime toy got released, he got "reinstalled" as the Autobot leader in European fiction.
Trypticon's component robots, Brunt and Full-Tilt, are never referred to as separate characters during the series. They are always seen as parts of Trypticon's body, and never detach from him. Brunt is a small tank made up of several towers and guns on Trypticon's city form, while Full-Tilt is the purple-colored car situated on Trypticon's dinosaur mode chest, who could transform into an actual robot.
The Autobots, most recognisable human friend, Spike Whitwicky, was aged in his late teens to early 20s in Seasons 1 and 2, because they were set in the years of production where in the movie and the final 2 seasons he was older because they were set 20 + years into the future
Megatron actually does not transform into his gun mode very often. Instead, he stays as a robot and uses arm mounted fusion cannon. The series placed greater importance on Megatron's motives to attain absolute power.
Unlike Optimus Prime's trailer, which mysteriously comes and goes between transformations, Megatron's silencer and stock can be accounted for when he transforms from pistol to robot. In the episode "Day of The Machines", and "Transformers: The Movie," the components simply drop to the ground nearby. In "Day of The Machines" when Megatron transforms back to robot mode in the storage cage, the components drop to the ground and remain in frame behind both he and Soundwave.
The trivia item below may give away important plot points.
In the eponymous serial comics published by Marvel Comics between 1984 and 1991, it's revealed the origin of the Transformers. They were created by a god-like entity named Primus. Primus has been created as result of the Big Bang caused by the rests of a former universe which was destroyed by Unicron, god of destruction in those place. Unicron, who was in a hypersleep by the belief that his work was finished, awake up to destroy the new universe as well as he did with the previous, but Primus faced battle to preserve it. Seeing that their confrontation was destroying the universe, Primus moved to Astral Plane, knowing that Unicron should follow him. Looking for a way to defeat him, Primus deceived Unicron for his return to normal universe, and both were trapped in rock asteroids. Using his power, Primus turned the surface of the asteroid in a planet, called him Cybertron. Realizing that if he could do it Unicron too should capable, Primus created a race of robotic living beings called Transformers as a replacement of himself, using his lifeforce to create the Matrix as the definitive weapon to be used in the last battle against Unicron.