I had been taken for a fool! I never studied Titans Return Legends Class Brawn's stock renders very closely, but I did note that he had his spare tire on his arm. Aha! He must transform asymmetrically! That is interesting, I said!
Ah-heh, actually, no, the spare tire section just pops off during transformation and pegs onto his arm. He otherwise transforms exactly like you'd expect Brawn to: Arms pull out from sides, legs fold out from back. Done! He is not a complicated guy. Even if you remember to flip out his heels, he's still not a complicated guy. This is somewhat of a relief, given how much more fiddly the other Titans Return car guys like him are, such as Bumblebee and Wheelie.
The main difference between them and Brawn is Brawn's passenger compartment for little Titan Master guys doesn't compact. It's left alone during transformation, meaning you can keep your Titan Master Brawn inside him if you want and never remove him again. It also means his torso is a little long, but whatcha gonna do.
If you don't like Brawn keeping his spare tire on his arm, you can also choose to peg it on his ass.
Brawn is versatile.