I took a random photo from an ebay listing for a 2004-2006 X3 MT.
Not sure if this is the same MT for your X3, but this is to show the location of the Hex fill plug...


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I'm pretty sure that is not the fill plug.
That height would require 10 gallons of fluid to reach that high.
That is not even a bolt, if you look closely.
The fill plug is at the bottom, slightly to the right of center.

https://www.newtis.info/tisv2/a/en/e...earbox/DfjP3XR

https://www.newtis.info/tisv2/obj/1KIylHEV

OK,

Just redid the photo.
Blue should be the fill plug...

Yes, that is the location, I personally stripped it myself.

IMO, just abort the project and move on...

I thought you already took out the fluid. +1 on the wait. Our 2001s are both on factory fluid with AT at about 175,000 miles. With MT I wouldn't worry about it for a couple years.

I noticed the head of the bolt sticks out that wil make it much easier to eventually remove with a pin punch and hammer.

Yes, I understand this is not critical, and I can drive on 100k mile MT fluid for a lot longer.
However, at my convenience, I will get a shop to remove the plug.
I dislike owning a car with a stripped plug with fluid that can't be changed.
That is a symbolic start to of a path of neglect or something.

I have a set of these, stubby extractors, they work great. Use a long-pattern ratcheting box wrench. I'd spray it with Kroil/PB Blaster.

https://www.amazon.com/Irwin-Tools-5...TSN62PDJKAMDBB

I’m with you. It would just bug me, and the MTF doesn’t last forever, plus you cannot check fluid level

Order a replacement if you haven’t already, and I would grab an air chisel from harbor freight, heat up the plug a bit, and have an assistant try loosening while you bite on the edge of the plug with the air chisel helping you turn it. The drain plugs turn very easily once they break loose.