Lock the rear and either leave the front open, limited-slip or if you must lock the front be gentle on it. If you don't replace the birfs with Longs or something similar and hammer your rig it is only 1 rock away from exploding. I have never (except in my Sammi) locked a birfield equiped truck. Stock birfs are fine as long as you keep the load centered on them, that means don't turn the wheel till it locks and stab the skinny pedal.
