2017 Chevrolet 3500HD DRW
21,553 miles
Out: FF grape scented 75w90
In: 50/50 mix of Starfire 75w90 and 75w140 full synthetic
The front diff took just shy of 2 quarts and the rear took about 3.5 quarts to get it ~17mm from the bottom of the fill hole. The rear diff was under filled, a little less than 3 quarts drained out. If you fill to the bottom of the fill hole, these 11.5 AAM rear ends will hold about 4 quarts. The proper level per GM is 17-21mm below the fill hole.