The repair manual says to fill the CVT to within 5mm of the bottom of the fill port. I'm wondering how important that actually is. How did Honda even come up with that value? Practically speaking it would be hard to probe through that port much lower than that with a finger. And how precisely can anybody determine how far a finger bent without being able to see it bend, or even feel precisely when it hit the fluid? Isn't the test really "poke in a finger and it should come out wet", regardless of the very specific depth range the manual gives. I believe there is an oil pump inside the transmission and presumably its inlet is far below the specified fill level, if not very near or on the bottom of the case. In terms of the mechanics, where is the "full" fluid level with respect to the center of the common axle of the rotating components inside the transmission? There is quite a bit of depth from the fill port to the drain plug, seems like the fluid level could be halfway between them and it would still coat everything inside which was spinning. Finally, one slightly related comment. I have now watched maybe a half dozen "change your CVT fluid" videos and in every one of them the fill port was in plain view, as in from peeking in under the bumper. Did they all remove the plastic shield on the bottom without saying so, or are a lot of people not bothering to replace those when they inevitably tear? In my car, with a completely intact front bottom splash shield, there was about 2-3 inches from the front face of the transmission to the trailing edge of the splash shield. I could only just see the side of the fill bolt head, when my eye was perfectly aligned to look through that gap. The fill bolt was removed and replaced entirely by feel, with my elbows below that gap and my face staring up at nothing useful on the back of the transmission!
I take the under shields off for transaxle fluid changes, oil changes too. Makes access much easier. (albeit on a gen 3) It's not that hard to achieve. The spec is zero to 5 mm below the lip of fill hole. You fill, with the car level, till it starts spilling back out.
It's not an exact science, but a best effort guess. The more sloppy you are and less rigid you follow the specs - the more likely your outcomes will not be good. For example; I did an ATF change on a VW and followed all OEM specs; including rechecking the fill level at a certain temperature. The results was a slight slip, when starting off below 35F for the first 5 minutes. I reasoned out that the ATF level must've contracted from the cold, after some friction, everything else started to function normally again. This was 4 month after the change. To test my hypothesis; I blindly added a cup (8oz) of ATF to the transmission. Problem solved, no more cold start slips..... YMMV.... FWIW: this was also a life-time ATF transmission w/o a dipstick. An allegedly sealed unit too.
It's like filling hypoid rear end of GTO fill it till it runs out or close . Level car rest comes out . Cap off. Done if on a lift easy . Not to bad to put plug in after lowering though in driveway
It's not good to run without the undercovers. It affects the airflow through the condenser, engine and inverter radiators. Oiling the gears is not all this oil does. It keeps the electric motors from burning up or shorting. Since there are no clutches or sliding/engaging gears in a Toyota eCvt wear metals are not a concern.
One trick I do when filling transmission fluid, I drain into a clean container and then use a measuring cup to transfer the spent fluid into a gallon jug collection for curbside recycling. I keep tabs on how much fluid I captured. Then when I refill, I pour roughly the same amount of new fluid back and then watch for the drip as I get close.
The 1/2" ID vinyl tube that was used to fill the transmission was a pretty tight fit for the fill hole. On the plus side, that helped to hold it in place. On the negative side it may have resulted in a slight overfill since the fluid had to not only rise to the level of the bottom of the hole, but also a bit more so that it could find an opening to leak between the tube and the transmission case. I didn't remove the tube while the vehicle was flat (because it was held up at that point only by the floor jack and partially by wood under the wheels). So after the car was raised and put on jack stands, and then the tube pulled out some of the dripping could have resulted from that tight seal and a bit of extra fluid. Or not, because it also dripped in the same position, and about as much (very, very roughly, there was no measurement other than by eye of fluid in a large pan), when the fill bolt was removed before draining the old fluid. That old fluid was put in by a shop, presumably with the car completely level on a lift. However they filled it, at some point the fill tube would have come out while the car was level and it would have drained to the bottom of the bolt hole.
I've done a gen3 & gen4; both took around 3.75 quarts - before dripping out. If you put at least that much back in; you should be good...
OD is the critical number, 5/8” is the most you want to use. Just looking up tables, that’s likely what you had. I used same and there was some clearance, enough for it to spill when full.
