They're both 23mm on the trans behind the 2.3...I don't know why they'd be any different on the one behind a 1.6. I wasn't sure, so ordered a 23 and a 24. Now have a 23 that has probably seen all the use it will ever get, and a 24 that's brand new still, but I procrastinated doing the job past my return window, so couldn't return it. Haha
Part numbers, I have no idea. I just reused my drain plugs and washers and have had absolutely not the first drip in the last 6k miles since I changed the juice inside. The washers are aluminum, they should be good to seal a few times. Just change them when/if they're obviously deformed. I believe the torque spec for them is 30 ft/lbs? Maybe 25, it's been over a year since I did it.
