On my 2004 Ultra, I have a Corbin 'fill hole' (don't know what they call it).
It replaces the inspection cover. I drain the Primary oil from the drain hole, pop off
the Corbin cover and refill with a quart of whatever oil is popular on this forum.

 

Can't hurt anything by doing so. And it ain't hard. It's right there waiting for you with the cover off (during the fluid change).

Even if it don't slip, the "more accurate" adjustment leads to smoother shifting and easy to find neutral.
Smoother shifting is almost as good as sex.

 

The most popular oil on this forum? There are so many popular oil's on this forum, that You must change brands at each oil change. lol

 

Ok...Great info from everybody!...Went by the dealer and picked up 4 quarts 20/50 HD oil and a filter plus the filter tool....Went home and looked at the owners manual and figured out which of the half dozen bolts was the oil drain and wala! Drained the oil....Used a cut up Bud Light 12 pack (from another night) carton to place under the filter to catch oil spill which worked pretty good. Replaced filter and put about 3 1/2 quarts in the dip stick hole and we're done!....Next is the service manual and some dvds.....Thanks again everybody that posted

 

Hell....I just use my pump that I change out my outboard boat motors lower drive unit oil with. Attach right up to the primary drain hole and pump the oil in.

just kidding...it's a thought though.

 

On a 2010 Streetglide you have the engine oil, the primary oil and the transmission oil. Check your service manual for proper change intervals, and yes they all drain and fill from different places. If you use a synthetic you can use the same oil for all three (SE SYN 3)