Place the chuck roast directly into the crockpot. No searing needed.
Sprinkle the au jus gravy mix and ranch seasoning evenly over the roast.
Layer the sliced butter on top of the seasoned roast.
Pour in the pepperoncini juice and add the whole pepperoncinis.
Cover and cook on high for 6 hours, without lifting the lid.
Once the roast is fork-tender, shred it directly in the crockpot and stir to coat with the juices. Serve warm.