We need to know whether it actually is a Diplomat before we can discuss it, sorlawn. Scott Bonnar provided an aluminium replacement as a service part for a time, then a mower repairer sold fairly awful steel "gears" (they didn't really qualify as gears, but they did drive the roller) for years, until just months ago. I don't know of any remaining new ones available. However if you search "diplomat" in our archives, you'll find several threads giving details.
