If there was a dragging brake before take off you'd have thought the crew would have had visibility of this (brake hotter than the others) on the brake temperature page.
The gear page is not displayed for T/O, a taxi from T4 to 27L is very short and I would not expect the brakes to get very hot in that short a distance. The Eicas caution comes up around 5 units (I think) which is equivalent to an RTO at 120 knots at max weight, so probably unlikely to come up during a T/O.