New member here and also a first time truck owner. Have a question about my 2002 Ranger Edge. When accelerating from a complete stop turning left or right, the rear wheels will sort of lock up. creates a shutter feeling and makes the tires squeal. Dont mind my bad truck knowledge, I've never owned one before until this week. I drained some gear oil out of the rear end and put some Motocraft Friction Modifier Additive in. Ford dealership told me to go do a few figure 8s in the parking lot and the sound and shutter would stop. Alas, the sound did not go away. I'm not sure what to do, someone help!