pjigar wrote:
I was so concerned and confused so I called G2 technical support. The G2 rear differential part number is 40-2029ALB. According to G2 technical support: G2 40-2029ALB rear differential cover takes factory recommended gear oil fill. They also said that their fill hole is set "higher" than factory! That got me thinking so I went back to OEM cover and put it side by side with G2 cover. I realized that I measured the OEM cover fill hole incorrectly. The OEM fill hole bottom is 3-3/8" from the bottom of OEM cover cavity. I am so sorry about measuring the OEM cover fill hole height in incorrect direction before, I had the cover turned 90 degrees.
So in summary: G2 cover has fill hole set way higher at about 5-1/2" compared to OEM fill hole at about 3-3/8". The correct fill amount for G2 cover is 4.4 pints (factory) or 2.2 quarts.
They do that since in most cases your putting a aftermarket HD cover on after lifting which will tilt the rear diff requiring the fill hole to be raised otherwise you will not be able to get the correct amount of oil in the rear diff.
Try filling my rear diff,Curries RockJock60 with the diff cover at a 60 degree slant the complete opposite way.