I am changing the translate fluid and read it should take a little under four qts. I put four qts in and it didn't overflow any. I did use a little pimp that screws onto the bottle kinda like a hand soap pump but there isn't hardly any left in the pump so I didntmlose much there. Any ideas? And yes I'm sure I put it in the correct hole. Edit- never mind. Just checked it and it's about 1/16-1/8 below the lip. It should be fine.
This DIY thread says the refill spec is 4 quarts. If that's the case, and you've not spilled any, you should be good. Toyota Prius: How to Change the Transmission/Transaxle Fluid - PriusDIY.com In the link he really dwells on determining the right refill quantity by measuring what came out. This seems a bit misguided, I mean, it could be low to begin with. My method, with 3rd gen, is get the car level, pour in 'till it starts coming back out, then let the overflow subside for a while, then replace the bolt, good to go. With 3rd gen that's around 3.5 liters, in my experience.
Gotta love auto correct. Guess I should have read it before posting. LOL And yes it was on ramps when it was filled so I am sure that has something to with it.