Cook the pasta in well-salted water until just al dente, following the package timing and checking it after 8 minutes. Avoid overcooking because the pasta will soften more as it absorbs the dressing.

Drain the pasta thoroughly, then rinse it under cold water to stop the cooking process. Let it cool completely so it will not thin the dressing or make the finished salad watery.

Whisk the mayonnaise, sour cream, dill-pickle juice, garlic powder, salt, and black pepper in a bowl until smooth and well blended. Taste carefully and add more salt only if needed, since pickles and pickle juice already bring plenty of seasoning.

Place the cooled pasta in a large bowl with the chopped pickles, cheddar, red onion, and fresh dill. Pour the dressing over the top and toss until every piece is evenly coated.

Cover the bowl and refrigerate for at least 1 hour, preferably 2–4 hours, so the flavors can mingle. Stir again just before serving, adding a small spoonful of pickle juice or mayonnaise if the salad has thickened.