An important aspect relating to Wurlitzer gear box lubrication, even
to the extent of proper lubricant choice, is clearance, tolerance, and
setup.  Bushings must be round, and with parallel centerlines between
adjacent bushings. Axles and journals must  be essentially round as
well. "Round", relating to bushings and journals being discussed here,
might reasonably be defined as a maximum of .0001" difference between
major and minor (external/ internal), diameter.  Bearing clearance
should be in the neighborhood of .0005" - .001" (bushing diameter minus
shaft diameter). A rule of thumb is to provide ~.001" clearance for
every inch of journal diameter.  With these conditions met, even with
relatively low surface speeds, and low viscosity oil, a level of
hydrodynamic pressure will be realized as well as static oil retention.
This will result in silent operation and greatly extended life, with
reduced criticality of lubricant properties.  My recommendation for
oil would be straight 30 w.
greater clearance.

Alan Erb

PS: Amendment to earlier comment:
...increased viscosity lubricant is appropriate in situations with