Custom Gearbox is very loud

[Tottanka]

So we just build our first ever custom gearbox, and it's one of the "opened" once. As in, you can see the gears and all, and when testing it we feel like it's very very loud compared to anything wev'e had before.
Now, all our previous gearboxes were enclosed once, like the ballshifter for example.

So what we want to know, if that loud noise is just how it is supposed to sound like with an opened gearbox, or is that means that something's wrong.

Thanks!