When you use the Associated diff screw what do you use for thrust balls and washers ??? I use Yokomo in mine, I also use aluminum out drives (Diff halves)
I run mod and I like my pro4 and my Cyclone but the diffs should be more like the XRAY I think. They have wave washers instead of a spring. I have made all the changes that have been suggested and I have a hard time keeping them from slipping.