[quote=@pyroman]
to be honest, I think that pain would be more a mental thing than anything else in regards to transformers. I remember specifically the team trainwreck comic posted on here where a little bot lost his legs or something like that, and considering that they don't seem to need their legs (or any real appendages for that matter) to function, visual stimuli would seem to be the best, if not the only way to tell if they were injured, unless, of course, the were hit in the chest or the head. 
[/quote]

Perhaps that is one method to verify damage. We can see that Tailgate (the little bot) also had internal readouts that also informed him what was going on as well. However in that scene, we only seen the aftermath of his accidental tumble that put him in that predicament. But with your later statement, yes, Transformers do not require their limbs to function so long as their head and most of their main body remains intact.

[url=https://youtu.be/Ssw9xCcMp1M]Also, here is Starscream blowing his foot off.[/url]