Welcome to my world James...

Had the same thing happend to me recently in my 1998 300 TDi with 195,000kms. Do a search to find out more detail...

The mainshaft sheered off behind 5th gear and of course the bit that sheered off decided to fall into the tansfer case and chew that to pieces as well...

So after $6500 of repairs...my truck now moves forward like it should...

I feel your pain...

Andrew