I got this Fit a week ago. It's an auto with 125k miles. It was shuddering when shifting and making this weird growl sound in 2nd or 3rd gear from time to time. I did a drain and refill with Valvoline Maxlife ATF and now it shifts very smooth.
I think the fluid was never changed.

 

Nice car! When you drain and fill you only change a portion of the transmission fluid, unless you pump it out. My recommendation is wait a couple weeks or so and do the flush same as you did. This time though change the transmission filter. You can see it after taking out the battery.
As luck would have it this recent thread has a good picture of it:
https://www.fitfreak.net/forums/2nd-...-2009-fit.html

You can see the in-line filter bracketed down with a large rubber hose connected to it. The filter is cheap. Kind of a pain to change, but not too difficult. I changed mine around 100k.

 

Thanks for the info!

 

Very nice looking car! Hope the fluid change remedies the shifting issue.

 

It did Vern...Now I'm noticing a slight thunk or thud sound coming from the front right suspension only when no weight is on the wheel, like when coming off a small curb. Any ideas? I don't feel any play in the sway bar links. Hope I don't need new struts.