So you want the slipper to slip before the diff does. Makes sense. But what if the slipper is very loose and still won't slip? Gearing is 26/81 on a 3300kv Ready (the kind that comes with the RTR).

There is no binding anywhere.

Is this likely a ESC tuning issue, or a gearing issue, or something else? I feel like the diff is very smooth, I'm hesitant to tighten it... Ideas?