Thank you for your replyCould just be your battery making an annoyingly grand exit. These cars are sensitive to voltage and your haven't done any other mods then that's where my initial focus would be.
if you're able to charge the battery then I would do that and clear the codes and see what happens.
Have you tried clearing the codes yet? Did they come back immediately? If the codes didn't immediately come back then I would guess all the gears would work again.
I cleared the codes, went for a drive still only the odd numbered gears with Tcm malfunction displayed on the dash guess I'll be having a learning week or two on the ins and outs of the GT-R. No codes were displayed on the ecutek when I re-ran the dtc check. Car isn't mapped and has not been launched according to the ecutek.