The PG-rated 1986 Transformers movie is not only chock full of graphic Family Unfriendly Violence and Family Unfriendly Death, but also cursing, eg "Oh shit, what are we going to do now?" and "Open, damn it!" Granted, you can still get away with this sort of language in PG-rated movies today, it's less common than it once was. The fact that this was based on a children's carton (and was meant to be a kid's movie) probably kept the rating at PG instead of PG-13 (which was introduced in 1986).
To be fair, the original VHS release had two versions; an uncut "Collector's Edition", and an edited one that had the "Oh Shit" removed (and replaced by a rather awkward silence).
Another bit of swearing that's frequently overlooked: The Touch, a song featured prominently in two scenes of the film, includes the line, "When all hell's breaking loose, you'll be riding the eye of the storm!"
This actually carries on to the G1 series when it's played in the finale (when Optimus opens the Matrix to stop the Hate Plague. The use of the word "hell" is not removed.
There's also the line in G1's "Prime Target" that managed to sweep by. After Blitzwing is caught in the hunter's slime trap, he's flailing about and screaming at Astrotrain to help him. Somehow, the voice actor managed to get a very muffled "damn!" into the line without the censors catching it.
"Prime Target" is also the source of the immortal line:
Optimus Prime: Amazing! A booby trap that actually catches boobies!
In the original pilot "More than meets the eye", when Optimus and Megatron are fighting on top of the dam, Megatron asks "Any last words, Prime?". Optimus replies "None you'd want to hear, Megatron!"
In "Triple Takeover" Blitzwing thinks a football coach is a Military officer and tells him "Tell me what's on your mind or I'll splatter it on the wall and see for myself!"
In "City of Steel" They PARALYZE Optimus and cut him apart while he is CONSCIOUS. Megatron then reactivates his SEVERED HEAD and TAUNTS HIM. Later Most of Optimus's body is rebuilt into an alligator-con, his legs are severed and the autobots manage to save him by rescuing his STILL ALIVE AND CONSCIOUS SEVERED HEAD from the shelf they put it on. After reassembling him, they retake the tower that's using his SEVERED arm and gun as a weapon.
They probably only got away with it because he's a robot - a sentient robot, but a robot none the less.
Dick Gautier once made a joke about certain names in the franchise: "I played 'Rodimus Prime', and I have no idea how that name got past the censors."
"Fire on the Mountain" from the original G1 seems absolutely rife with suggestive imagery.
Prowl: "I've got the plan, if all of you've got the cast-iron manifolds for it!"
Wheeljack: Hang onto your crankshaft, I'm switching into overdrive!
It is heavily implied in "Only Human" that Rodimus Prime had sex with Michelle while he was in a human body.
Transformers in general often gets away with a lot of cursing by substituting certain anatomical references for the nearest mechanical ones.
Beast Wars was particularly good at this. Words such as slag, frag, or scrap were substituted where a human might use harsh profanity.
In addition, Rattrap had a habit of making comments that we're still not sure how they got past the censors. He invites Tigatron to come to a bar that he described as a "hole in the wall". Later on he invites Silverbolt to a bar where the females don't wear their chestplates and makes a sort of leering wink. After being upgraded to a new form, with the others staring at him, he goes, "Is my gearbox hangin' out or somethin'?" When Silverbolt comes back from an illicit meeting with the Predacon Blackarachnia and claims he was simply scouting the area, Rattrap sardonically replies, "Ooh, scouting the area, were you? Find any new... positions?"
"That guy must have bearings of chrome steel".
There is also the remark about a "positron break" when Cheetor developed his crush on Blacharachnia. Then there is the Ho Yay moments with Rattrap... too many to list.
In the episode "Dark Designs" when Waspinator is hallucinating about being Shrapnel and says the famous line "No, not wacko... Wonko! Wonko the Sane!" Look very, very carefully at where he puts his hand, and try not to fall off your chair laughing, like I did. The very best part is that he gets AWAY with it!
Blackarachnia's original design herself in Beast Wars has an amusing story behind it. Essentially, the crew went to a strip club one evening and when they got back to working on the show, Blackarachnia's design was finalised after being "inspired" by an Asian exotic dancer at the club.
In the episode "Double Dinobot" of Beast Wars , there is a display that has some text on it in one scene, close examination reveals it says "hey Ian go f*ck yourself". WOW!
In an episode of Beast Machines, Thrust pretty clearly flips off Optimus Primal, especially judging by Primal's disgusted reaction.
In one episode of Beast Machines , during an argument with Botanica, this happens:
Botanica: And what would you rather be doing?! Sticking your tail in a computer socket?!
Rattrap: Heh, beats the heck out of plowing your little field of dreams!
The Unicron Trilogy
Okay, what about Transformers Cybertron and Thunderblast's boobs? In one episode, there is a scene where she has visible nipples. Oh and they bounce. Did they drug the censors or something?
Transformers Animated has the episode "S.U.V.: Society of Ultimate Villainy", in which Slo-Mo remarks to Nanosec after watching him zip in and out of a building to steal something for their benefactor, "I like a man who works fast," to which he responds, "And I like a girl who takes it slow."
Not to mention Prime's reaction to Sari's answer to his question as to how human reproduction works.
And of course, Blackarachnia (who, it should be mentioned, has Cree Summer's sultry voice), in "Along Came a Spider", sneers, while fighting Optimus (effectively an ex-boyfriend, or a could-have-been boyfriend), "Much as you'd love to give me a faceful of [fire-retardant] foam..." ('Cause, y'know, he's a fire truck.) And then, shortly afterward, he does. Yeah, it's white. And she does not like getting it in her eyes...
In "Predacons Rising", Sentinel barks at Jetfire and Jetstorm to stop standing around with "your pistons in your servos", which is essentially a Cybertronian version of the phrase "dick in your hand" *
(i.e. to be standing around doing nothing, when you should be doing something more constructive)