Don't forget to make sure the cam gears on the left side are engaged so they will allow the right side to separate as far as it can. Also give a tug on the left side axle shaft to make sure it is all the way out. I don't remember if it is in the instructions or if I read it some where else, but make a separator out of a metal clothes hanger. You shouldn't need any different shims. If you still can't get it call Dave at Northridge 4x4, they are one of the top distributors and should be able to offer advice.