Well, I pulled the box apart, Found that a Part called shift insert had come out of the synchro hub. I think that came out because the shifting insert spring broke. The shift insert has done a bit of damage to the cluster, eveything else seems ok. Can get a brand new cluster for $700, A kit for $500 (main bearings seals gaskets, needle roller bearings and inner sleeves), new shift inserts $66 for 9, and the new spring inserts $6. About $1300 in total with me doing all the work.
cheers
Leigh