I believe the Micro Minnies are all dual axle.
Don't forget the DEF level reset procedure after topping off.
I’m 2500 miles into a trip pulling a 4K lb trailer at altitude and it is sucking DEF like mad. Is there a better DEF filler tub out there? The 2.5 jugs available at most stations dribble and you can’t see how full you are. 2016 tdi t’reg
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One of the conditions of the Dieselgate fix is that VW has to fill your DEF for free (I forget if it's for life or up to 100k miles). So the only time you really need to fill it yourself is if you're on a long trip and it gets low, and you don't want to bother with finding/dropping by a local VW dealer. On top of that, DEF has a shelf life. So unless you know you're low enough that the entire bottle can go in with no leftover, filling at a truck station is probably the better choice.