99 deville with northstar v8.....intermittent on starting from stop I feel and hear and ratching/clicking sound and traction control light and/or anti skid warning comes on. mostly happens on wet roads but NOT always and this is not quick acceleration but easy start from a light or stop sign.....what could it be and how do I test for it. no codes shown by autozone and they said need tech 2 for this problem to identify...thanks.