If your cleans tend to crash onto your shoulders, even with lighter weights, you can smooth out the turnover and stay better connected to the bar by holding a full grip longer (If you keep a full grip in the clean already, you have other problems to work on if the bar is crashing on you).
If you release your grip in order to rack the bar with only the fingers under it, releasing too soon creates disconnection and makes it easier for your shoulders and the bar to become separated more than necessary. Try to delay opening your hands until the elbows have come around under the bar and are beginning to move up into their final position—the longer you can wait, the better. At this point, the bar and shoulders will be in contact (or very close to it) and the grip is no longer needed to control the bar—gravity will continue guiding it down onto the shoulders.
Practice with tall muscle cleans (a muscle clean in a standing position with no leg or hip extension to elevate the bar), muscle cleans
and tall cleans
to get some practice and confidence.