Wilton, if the differential plug is 14mm, then I'll be set when it comes in. I do need to check the 90w level soon. I tried everyone locally, Pep Boys, Auto Zone, Sears none to be found. That's when I had a friend with a shop order one from Snap-on (after checking all his tool drawers). Also, the local Auto Zone has not been of much help on any of my vehicles as far as parts go.
I too tried to make a suitable tool. I didn't have any hex stock to bring down to size, but I did try a bolt. Couldn't find a bolt with a 14mm head, but found that with care I could slip a 9/16 headed bolt in the recess. Then I took two nuts and a lock washer, jammed them together as tight as I could and gave it a try. The length of the bolt caused it to wobble and when I used a wedge to keep it level, I could get enough force on it to turn the nuts, without loosening the fitting. A noble experiment without results. A touch of air and the proper fitting tool should do it.
73 280 SEL 4.5