i've changed my gear box yesterday.... when i recived my car with the <new> gear box i freaked out..... my old gear box gears was as:
1 60km
2 105km
3 150km
4 190km
5 ???km
and the <new> one is:
1 65km
2 120km
3 175km
4 220km
5 ???km
so before i killed my self i told my mechanic to repair my old gear box.... wtf gear box did they gave me?

Maybe he only replaced your final drive. So that all gears are longer and that way you get a higher speed ate every gear.