Well, the bearing (#4) goes in the hub with a press fit. It captures the spacer (#7) between it and the other bearing (also #4) on the opposite of the hub. The inner sleeve of the metering assembly butts up against the inner race of the wheel bearing (#4). This allows the hub tangs to engage the metering tangs to drive the speedo. It doesn't appear you're missing anything. My DR is exactly the same. It's possible that it's simply time for new bearings. You don't appear to have sealed bearings. So, try to clean out some of that extra grease (extra grease is a heat sink) and see if the bearing balls show signs of wear or spalling. How many miles are on the bearings (bike)?
There are some simple thruths......and dogs know what they are - Joseph Duemer
Andy holds the lead. And he will, all the way to the Highway. Today is his day.