Cook the rotini pasta according to package directions until al dente, then drain and rinse under cold water to stop cooking and cool.
In a small bowl, combine mayonnaise, sour cream, pickle juice, onion powder, and black pepper, whisking until smooth.
Place the cooled pasta in a large bowl, then add the cubed cheddar cheese, sliced dill pickles, and chopped fresh dill.
Pour the prepared dressing over the pasta mixture and toss gently to coat everything evenly.
Cover the salad and refrigerate until ready to serve, allowing flavors to meld.
