It's normal for the drum to change direction at different points in the cycle. Depending on when it happens, it may be rebalancing the load or creating the necessary wash motion to clean the clothes.
If the drum appears "unbalanced" particularly during the initial phases of the spin cycle, but there is little or no vibration on the outside of the machine, this is normal. If the washer is vibrating during the spin cycle, and it doesn't correct itself automatically by the time it reaches Medium spin speed (or about 350-400 RPM), then it may not be properly leveled. Please click on the following link to view a short video that should help you to correct this issue: http://support-us.samsung.com/spsn/...
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