That is for tightening the play between the internal gears, and I understood that your new box steered to easy.
There is an article called "Pump it down" that shows how to lessen the power assist.
Here is a post showing the procedure, and I'll see if I can find the actual article for you.
Pump It Down....EASY
Yes, thanks Tb. I made the' pump it down easy ' thread a sticky in the steering and suspension section.
Here it is.