Hazet 2760, 14mm hex drive x 17mm box end. I bought it as a MB differential plug wrench, but it's useful for various other European gearboxes as well. Hazet is top-of-the-line in tools. This one is slightly soiled but unmarked otherwise and shows little wear and no corrosion. I purchased it to use with my older MB.
$55 on Amazon + tax
https://www.amazon.com/HAZET-2760-Service-Wrench-Chrome-Plated/dp/B001C9Z4BI