I just finished up my first transmission oil change after the install of the highly coveted Shotgun Shock. I was not sure how much work it was going to be but let me assure any one concerned about this, it was very simple and did not take long at all. It took far longer to let the oil drain completely than to do any other part of the oil change.
Here is a step by step for all my fellow Shotgun riders. I forgot to get pics...sorry.

1.Jack bike up ensuring that there is enough room between the arms of the jack for the shock to pivot out of the way of the transmission drain plug. I have the Harbor Freight Hi position lift to make this really easy. It works like a charm.

2.Remove the two front bolts and rubber bushings from the Shotgun Shock. If the bike was already dropped when you jacked it up it will pivot right out of the way. If the bike was raised, let the air out of the system and use a floor jack to jack the rear wheel up until the shock has enough room to pivot past the frame gusset.

I had the bike raised when I jacked it up so I dropped the air and used the jack to raise it.

3.Remove transmission oil drain plug. Remove transmission oil dipstick.
Let the oil drain.

4.Replace o ring on transmission oil drain plug after cleaning of any metal shavings (normal) from the magnetic drain plug. Replace the drain plug. Refer to your manual for torque as I cannot remember what it is right now.

5.Fill the transmission with new oil.
20-24 oz for 2000-2006 softails
32 oz for 2007 and up softails

Check oil level on transmission dipstick, replace dipstick with new gasket.

6.Pivot Shotgun shock back up and raise floor jack slightly to achieve proper level for the bolts the thread back into shock. Use anti seize on front shock mounting bolts. Don't forget the rubber bushings on the bolts(I forgot one).

7.Tighten front shock mounting bolts (I tightened them to 2 grunts today.

8.Sit back and enjoy your handy work and raise and lower your bike a few times for fun!

thanks!

Drew