Outer Limits 4x4 Board

I have a nissan 4.2 turbo diesel plate oct 2001 with 60,000kms and have recently heard of 2 instances where 5th gear has died without warning.

Is my model at risk and is there any history in the market place of this problem? If so, what should be my next step?

yes you are at risk, there is a tell tail of the gear oil going a browny color, before they let go. check with a nissan dealer to see if they still warrant this issue.