Diff codes

["Hill, Stephen M EDUC:EX" <Stephen.Hill@gems7.gov.bc.ca>]

Does anybody on the list have the cross references which tell what the
stamps on the differential case mean, in particula,  what the ratio is? I
know by taking the case apart the teeth can be counted, but it would be very
helpful to figure out what the ratio is before opening them up. 

Stephen