Your description is reminiscent of a few series from the 80s and 90s, but the specifics make it a bit of a puzzle. We're dealing with the era of heavy toy marketing tie-ins, and there's a good chance the series is either Japanese in origin or inspired by anime. 'Voltron' …

sounds like you’re talking about Megas XLR. It had that big red robot and the gamer dude who controls it with a car as its head. 'Chicks dig giant robots' – the theme song was my jam!