I went to the source. I called Honda support.
American Honda Motor Co., Inc.
P.O. Box 2200
Torrance, CA 90509-2200
Mail stop: 100-4C-7B
Telephone: (866) 784-1870
"Why does the Swing use 10w30 motoroil instead of gear oil like my goldwing and VTX?
After being passed around very courteously 4 times, (one sounded very sweet) I was told that uses a different type of transmission. Also that the drive uses the same oil as the engine (HUH????????????).
I told them it is a separate oil in the final transmission.
He said; "where did i find that in the owners manual?"
I said; It's in the service manual.
He said; The Swing uses different gears in the final drive than in My other two bikes.
he said ; honda recommends using 10w30 motor oil.
I said; thank you for your time. Hung up.
1. i did not get a satisfactory answer to my question.
2. The Swing uses straight cut and helical gears, similar to my other bikes.
3. I do not think that the four people do not know gears or the reason and spouted Honda manual recommendation.
4. I had my reflex final drive transmission apart and it had a very similar setup , it used gear oil.
5. ???????????? I guess the drama goes on.
I will continue to use synth gear oil.
My local honda shop uses gear oil also.. are they wrong?
maxB (who didn't get a satisfactory answer as to why)