2018 is 8th gen maxima?
In finding various threads and youtube vids, I have enough info regarding getting the two transmission filters and dropping the transmission pan and draining fluid.

everybody says measure how much fluid you drain out then replace just that much... I don't agree with that.

I have 50k miles on my 2018, I think it's low on cvt fluid, but I have no way to check because I have just the vent plug with no dipstick on the transmission tube.

my question: how do you check if the cvt transmission, at any given time, has the correct amount of cvt fluid when there is no dipstick?

If for example I deliberately drain some cvt fluid then bring it to the dealer and say transmission not working (when it was until a simple reduction of cvt fluid) how would the dealer check fluid level and how would they know how much to add to top off to the correct level?

can a [universal] dipstick wire just be inserted into the transmission tube to measure fluid level? At least to get a first understanding of where fluid level is; or is there a fill/vent plug on the side of the transmission case (like what would be on a rear axle differential) ?

 

I don't remember the specifics of the procedure off hand, but there is a plug which gets removed while the car is running and the trans is up to a specified temp. The car has to be raised, of course, and when the fluid starts coming out the hole it's at the proper level. There are some vids on the subject on YT.