this cogged ring replaces the stock transfer clutch clutch discs found at the rear of the 4EAT AWD Subaru automatic transmission, turns your AWD into a true 4x4, solid locks in the rear output shaft, all 4 wheels will now grip all the time, car will bind on pavememt, suggest a driveline disconnect or trailer your rig, a must for the serious offroader that wants the most traction out of your Automatic. When installing add a few old clutch discs to make up for the extra space.