If its a proper crunch then no oil will help you, if its just a notchy feel then changing oil might help.
Have a search though, this has been covered so many times as its a very common problem.
However I would not recommend Fuchs, it made no difference in mine and imo is just as good as the Elf oil that's in the box already. I would instead try some Red Line MTL as this is supposed to help iffy gearboxes change more smoothly.