Changing trans fluid in 3650

[scooter3]

I am putting in a new MGW shifter today and want to change my trans fluid at the same time. What type of fluid and how much is required? Also, can I just pour the fluid in through the shifter opening while I have the shifter out?

[BurnTire]

A quality Mercon.
I used Mobile 1 Synthetic ATF when I had a T-56.
Fill capacity should be in your manual.
You fill it to the fill plug and yes you can add it thru the shifter opening.