1996 nissan micra 1.0Ltr, Gearbox?

i have a nissan micra 1.0 ltr manual and i have recently had a new gearbox put in, my engine runs smooth but between 2 and 4 thousand revs between the gears 1,2 and 3 my car makes a loud almost screeching/whooshing sound. do you think it could be the gearbox again? and has anyone had simular problem? Any information, in this matter would really help because its really stumped me.