I have the same problem. The part number I was given by the Vitamix rep I spoke with is 000063. The problem is Vitamix won’t sell the part. I’ve looked for it from third party vendors and apparently Vitamix won’t sell to them either as I couldn’t find the part from any of them. Vitamix will let you ship the stainless steel canister to them and they’ll install the drive socket for you for $165.00. Or you can trade your perfectly good, except for the drive socket, machine in for a new one and get a $100.00 credit from them. It’s pretty obvious what they’re doing here.