For the most part, Transformers refer to themselves as "robotic", but there are instances of them calling themselves "robots".
Transformers - Live Action Movies
The closest thing any of the Transformers come to using the word "robot" is the Optimus explaining
"We are autonomous robotic organisms from the planet Cybertron."
However, we also see Sentinel Prime comparing their situations.
Sentinel Prime: So lost you are, Optimus. On Cybertron we were gods, and here they call us machines! Let the humans serve us, or perish!
This is not concrete, but this indicates they see themselves as more than "machines", and ostensibly, "robots".
Generation 1 Cartoon
Seaspray refers to himself as a robot twice in the episode Sea Change.
From the transcript:
Oh, Seaspray, my friend... I did love you.
You did? Really?
I think so. Wait a minute.
There. How do you like that?
SEASPRAY turns into a HUMANOID much like the TLALOCONS.
SEASPRAY's feet, however, are still ROBOTIC, and are stepping on one of ALANA's feet.
Sorry. Guess I'm still part robot.
But I like you as a robot. I was afraid that someone with a body like mine wouldn't be your type.
Never! Wanna go for a swim?
A short time later...
It's Megatron! Let's go!
Seaspray, no! You're not a robot anymore!
Meahahahah! Bye, bye, fish-face!
It's no use; I can't fight them like this! I think it's time to go back to my old robot ways and give Megatron the surprise of his life!
In the episode The Key To Vector Sigma: Part 2, Skydive refers to Ratchet as a "robot". To be fair, most of the Aerialbots generally look down on the rest of the Autobots.
From a transcript
I say we're still better than any Autobot! Or human for that matter!
Think so, huh? Then follow me!
My power's gettin' low, buddy. I gotta recharge!
Go on, I'll finish this up.
The robot ran out of power...
...but the human's still working. Where does he get his energy?
I found one quote where Bulkhead refers to the Autobots as "robots in disguise".
It occurs in the episode Loose Cannons.
I found a transcript, but it doesn't indicate specifically who is saying what, so I've edited based on my memory. I'll try and double-check this later tonight, but I'm pretty positive it's right. I know it's Bulkhead with the final quote as he's the only one who calls him "Jackie".
Optimus Prime: Any strike we make against the Decepticons must be carefully measured as a team, lest we risk endangering the human population.
Wheeljack: Are you suggesting we sit back and do nothing?
Arcee: You! Loose cannon! Your cowboy antics almost blew our cover.
Bulkhead: We're robots in disguise, Jackie.
All other instances of the word "robot" that I can find are spoken by humans.
In fact, in Darkness Rising Pt 1, Ratchet takes great offense and corrects the idea that they are "robots" built by anyone.
From another transcript (edited for spelling errors):
Raf: So if you guys are robots, who made you?
Ratchet: Oh, please We are autonomous robotic organisms From the Planet Cybertron.