I'm having issues with one of the project bike builds that I worked on this summer. I installed a rebuilt ( not by me) New departure coaster brake hub. When not pedaling ( walking the bike) the pedals are engaged and the front sprocket moves as the bike is moved. I tred to upload a short 10 sec video but the server would not allow it. Also when test riding the bike, pedaling seems fine, when coasting there is a discernable "wobble" or "grabbing" that is felt in the rear. What could be wrong here? Are the bearings to tight? Is it the reaction arm? Could it be the rear cog? I've installed other coaster brakes before and have not run into this issue. Could it be the internal brake parts? Any advice would be helpful.