I'm no expert but... better than the replies you've had.
Tweety, my trike has a full 3 speed VW auto. The unit has a front mount. You'll need the auto selection unit for the conversion.
The unit has a wire to the accelerator for kickdown. It also has a vacuum tube from its solonoid to the manifold. easy hook ups. Inside the solonoid is a small screw. that adjusts your kickdown points.
But there is also a large screw on top of the trans. I advise you dont adjust this. It is a pain getting the adjustment right if you change them because they work in unison.
The auto is robust and does its job. You may need to overfill the unit with fluid because if it is on the fill mark it wont be quite enough and can lose drive up hills. Another cup of oil is good and wont harm it. Use heat proof gasket glue on the pan gasket and you may need to retighten after a while.
I would enquire if your swing arms and body will fit the box. On trikes if they are to take the auto they are not the same swing arms etc. Hope this helps.
www.youtube.com/watch?v=HXwh4z8d66o
SUBARU ea81, VW auto, Detour camper
My ex girlfriend said "its me or a trike". Her big mistake.