I'd say it sounds more like the diff bearings than the layshaft bearing. These offen make the driveshaft seals also go bust and a telltale sign is the leaking oil from the driveshaft holes. Other thing is a badly worn speedo drive gear.


There you see a new speedo drive gear (red) and the heavy duty IB5 layshaft bearing (left) used to replace the original (right).


Here you can see how bad the diff bearings can go.

There you can find some pictures of my recent rebuild:
http://www.kolumbus.fi/ulpu.tuominen...ox/rebuild.zip

The only site I know about offering some help is JimHearne's:
http://www.quantums.info/gearbox.htm