The 10-speed automatic found in the F-150 and Chevy Camaro is part of a joint venture between GM and Ford. As part of the deal the automakers will share designs for two transmissions: a front-drive 9-speed headed up by GM and a Ford-based design for the rear-drive 10-speed. Ford says the new transmission offers more efficiency due to wider gear spacing and from reduced drag. Chevy, for its part, says the 10-speed in the Camaro ZL1 shifts faster than Porsche's PDK.
We've reached out to Ford for confirmation, but the company typically does not comment on future product speculation. As such, it's anybody guess which Mustang models could receive the new gearbox.