I did not do either of those things...

I have no idea what DIY I found and followed but it said that it was "really easy" and simply, drain, replace filter, refill and drive.

I re-checked the fluid, and low and behold, it was a little low. topped it off and took it for a spin. Seems like it driving fine now. No noises or anything. Its actually shifting significantly smoother now. Hopefully I didnt cause any damage. The noise it first made has me worried though...