gearbox problem ???

had a problem today and my 740 i would not go into 4th gear unless i pulled the shift back to 4 and put it back into drive and also the sports mode did not seem to respond, maybe coincidence but i had had a puncture and had to put a 17 " original wheel on and all the rest are low profile 18 " wheels..... could this have been the problem , as when i put the 18" wheel back on it seem to go ok again ??? or i have i got looming gearbox trouble ??