that is on the instructions. Whether or not you received them is another story, but it is mentioned.
Glad you got it figured out.
I saw where you have to grind the 2wd/4wd block but did not see anything about the high/low block. I very well could be blind though.
Kevin
*EDIT* I am an idiot, I went back and looked at the directions and it clicked. I ground the radius off of the other fork. I dont know how I misunderstood it but...