I remember some time back someone posted in the Q45 forum seeking help with transmission service and ended up buying a trans dipstick because all he had was the plastic plug and a stubby metal piece that barely extended into the tube. A dipstick that never dipped (I never got any pictures).
Much later I was helping another member with a transmission issue and he also said his car didn't have a dipstick. This second person was going to make a custom thing and asked me to take some measurements.

File this under "useful information I hope to never need to utilise".

First off, find your transmission filler tube. It is located on the back side of your engine block. It is the same side as the oil filler neck and although hidden from the front, should be accessible even with the engine cover piece still installed.
For US market vehicles, the dipstick is secured to the filler tube by a 10mm bolt. I have handled a few JDM drivetrains and they are as easy to remove as an engine oil dipstick. See the video at the bottom

[Pictures to be posted later, or just watch the video]

I'd recommend you immediately check if you have a dipstick. If not, get one before you need it.

• From a salvage yard
• From a JDM unit
• Make your own using these measurements

And here's the video. There might be something useful within.

For comparison and also out of curiosity, I checked the oil dipstick as well.
Note

• This 25-1/4" dipstick is from a 2006 M45
• I didn't get a chance to measure my 2003 M45 stick, but the JDM ones have been 1/2" shorter, so 24-3/4"
• The gent I took the measurements for said his 2002 Q45 was 24-4/5"

The variations were all at the top. The bottom where the gradations are, all have the same dimensions. Have you ever seen my video on the 2 types of VK45DE oil pans? Well, it's at the bottom of the post

Very informative. Thanks!

Thanks Q!

For those who have looked for a real dipstick, has anyone been able to buy one from Infiniti?

I have a few dipsticks from older projects. Some US & some JDM.
The part # for the US model one is 31086-CR900, superseded to 31086-CR90A (M45, Q45, FX45), but I wasn't able to locate them through my regular channels. I was curious whether anyone was looking for them/how readily available they were...before I got rid of what I have.