washer basket drive can not get out

how does it come out.is there a tool I need or what

Are you talking about this part or the part this screws on to? (drive block)

http://www.appliancepartspros.com/whirlpool-nut-lock-wp21366-ap6005824.html

http://www.appliancepartspros.com/whirlpool-block-basket-drive-wp389140-ap6008836.html

Video

http://fast.wistia.net/embed/iframe/9qqqnesm9w?controlsVisibleOnLoad=true&plugin[socialbar-v1][buttons]=email-twitter-googlePlus-facebook&version=v1&videoHeight=237&videoWidth=422&volumeControl=true&autoPlay=true