Okay looked at a older tube the inside looks consistent without the bushings in place I have a post from a year or so ago were I had some difficulties and ended up taking my tube apart but I was planning on doing a gear swap anyway so I took it apart but I don’t think I had to as the issues I had could have been looked at a bit more .I think your oakie will come out thinking that it is so far out maybe try if you can find a length of pipe to fit over the oakie so you could try to wiggle it from side to side then if you have your clamps tap from each side as it will need to come straight out .if you could wrap wire around the oakie at the bump from the centre of the length of wire then after a few wraps loop it from both ends to come out to the centre and and with the two ends wrap them to a bolt and use a slide hammer to see if it will budge.
