Reviving old post. SrHorn, did you complete the replacement as described? Nobody replied to this one . I am getting ready to attempt this swap myself. 2007+ LCI E83 atc400 TC into a 2004 E83. I’ve talked to 2 rebuilders and both said rear flange has to exchanged. I will report back with updates as I progress. If anyone has info to share, that would be helpful.