Well, one persons 'tick' is another persons 'rumble' etc. I wouldn't really describe my gearbox bearing issues noise as a 'tick. If you are worried, there is a good video on utube of a Jazz gearbox in full bearing racket, have a listen.
If it is still ok-ish squirt some molyslip gearbox additive in and it should quieten it down, it did for mine for quite a while.