Gearbox issues

Good evening all, first post so please be gentle! I've just brought a 2007 vrs tdi knowing it had a gearbox fault.

The issue it has is a noisy box and no drive in 5th. I've come to the conclusion that the box is goosed but unsure if it's a case of any 2.0 tdi box fits or do I need an exact replacement for the code that's fitted now (JMA)

All advise and knowledge is greatly received

Ross