Thank you, thank you, thank you

[Dirtstiff's F6B]

..there's a reason why there is a full oil capacity for the differential. This was stated.

Words escape me

If your usual negative, sarcastic comment about being full was directed at me, dont...

I would be glad to wager that I've had my hands on and in more MC and industrial, heavy equipment differentials than most.

Encourage the OP to change it and check it. Keep an ear - eye and touch on it and ride. Don't scare him buying trouble before any real ( doubtful ) damage is detected.
These rear ends are tuff.

If not directed at me, I apologize.

[willtill]

If your usual negative, sarcastic comment about being full was directed at me, dont...

I would be glad to wager that I've had my hands on and in more MC and industrial, heavy equipment differentials than most.

Encourage the OP to change it and check it. Keep an ear - eye and touch on it and ride. Don't scare him buying trouble before any real ( doubtful ) damage is detected.
These rear ends are tuff.

If not directed at me, I apologize.

If I had quoted you... it would have been personally directed at you. Which I did not.

O.P. knows what he needs to do. His decision.. based upon what has been replied to him.

I do not appreciate the slight you have levied against me btw...

[Steve 0080]

This has been debated many times...a lot of diffs are sent out low... when is the last time you personally know of one that failed? I only know of one...Keep riding...

[druggr]

On GL1800s the rear end fluid is a static read. If the rear wheel was spun just prior to checking it, it will read low. It take a few minutes for the fluid to drip from the gears.

Yes, checking its level is part of a PDI (pre-delivery inspection). The next check is not part of an oil change, but it is part of an 8,000 mile service. Some confuse services with oil and filter changes. Services are more expensive, take longer, and usually follow a manufactures maintenance suggestions.

For whatever reason there seems to be a myth about molly added at the factory. There's probably no truth to that myth. However, various products are used when setting up the final drive (adjusting the ring and pinion), and some might confuse that product with an additive. Since they are of no harm, such products are often not cleaned off, but end up getting mixed in once the 80w-90 oil is added. A good example of such stuff is the assembly lube found in the bottom of the rear brake master cylinder. It gels and collects in the bottom of the reservoir. Its very visible when doing a the first brake fluid change at 12k. Some is usually still found when doing a 3rd brake fluid change at 36k.

With Honda's brake recall, and after its been completed, assembly lube is now collecting in the reservoir all over again.

[crossbowme]

Well, after reading this thread, I changed the rear end oil. Same results as everyone. Glad I did, I'm leaving on a 1500 mile trip.