Trafic 1.9dci 100 gearbox issue

So the gearbox on my 2004 trafic went from being noisy to finally going bang.
I have now got another pk6, but it's a pk6018 from a Laguna. My old box is a pk6025. So my question is will it fit & how much difference is their in gear ratio?

Thanks

Trafic 1.9dci 100 gearbox issue