For MB transmissions that lack a dipstick (having only a cap on the tube) this can be used to check the fill level. This one has never been out of its wrapper. Purchased in 2016. I assume that it's part number 1405891521 . I had intended to use it on a W210 '99 E300.
I'm moving out all my MB tools, and this was in the drawer with them. It's almost certainly a genuine MB part, but I can't find the receipt so I can't prove that. Aftermarket ones are around $13 new.
Contactless porch pickup. I'm about nine blocks north of downtown Oak Harbor.
Info from an Amazon listing:
https://www.amazon.com/Homesweet-1405891521-Transmission-Transmissions-Mercedes-Benz/dp/B0FN6XLDFS
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Part Number: Fit for Mercedes-Benz 1405891521,168589012100. Manufacturer Part Number 917-321 120-0721. Interchange Part Number 140-589-15-21 140-589-15-21-00
Fit for Sprinter 2002-2017.
Fit for Mercedes vehicles equipped with the 722.6 transmission;
Fit for Sprinter in 2500 or 3500
Easy to Use: Total Length: 1220mm/48'' & Length of the tool: Approx. 46''. Simply insert the dipstick into the dipstick tube, remove, and check the fluid level like any other dipstick. This dipstick is marked with hot and cold readings for ease of use.
Note: They are not designed to be left inside the transmission. They are only for checking fluid levels and then removing. This is a tool, not a replacement part .