Motortrend provides some reasoning behind why they believe the upcoming F10 M5 may be M-division's first automatic-only model, featuring a ZF 8-speed automatic transmission only and no manual or dual clutch transmission option. (Thus far, the F10 M5 has only been
spotted with automatic transmission)
Their reasoning for the lack of a DCT option is due to the monstrous torque that the F10 M5's twin turbo DI 4.4L V8 motor (S63) from the X5M/X6M is expected to generate. The F10 M5 is expected to feature more power than even the X5M/X6M which currently puts down 500 lb-ft torque, and could come in above 550 lb-ft. Apparently, BMW attempted to adapt the Getrag M DCT for the F10 M5 but was unable to do so without beefing it up with larger actuators, which would result in an unacceptable slow-down in the transmissions' response/shift time.
Motortrend does not provide their reasoning as to why a manual transmission option will not be offered, but the general thought that has been posted on our forums previously is that there are not or will not be enough interest from F10 M5 buyers for a manual option.
Of course, none of this has been officially confirmed and until then, it remains speculation. But, it won't be long until we know for certain which transmissions the M5 will or will not get, as the production F10 M5's internet reveal is expected this Summer / early Autumn, with the production M5's world premiere at the Frankfurt autoshow in September. We may even find out earlier than that when the concept M5 is shown at the Shanghai Autoshow in April.