Showed up all at once? Don't know how old or total towing mileage you have but it could be the eye of the spring bushing cracked or worn out or you could have caught a curb bad with that axle and the bushing or hanger or bent axle. My vote is in the hanger area because that axle, if used much has more stress, from jacking it around, to back in and sharp turns forward. That tire also gets more stress on belts. Check the tires first then the hangers and bushings and springs and then axles.