Some 2019-2021 Edge/Nautilus, 2020-2021 Escape/Corsair, 2021 Bronco Sport vehicles equipped with all wheel drive (AWD) may exhibit chatter/shudder during low speed turning events due to fluid contamination. Drain and refill the rear drive unit (RDU), refer to Workshop Manual Section (WSM) 205-02. Drive for 8 km (5 miles) in stop and go conditions with right and left turns and re-evaluate. If the issue is still present, continue with WSM diagnostics. For claiming, use base (4000) causal part.