Hei. I think it is possible. You have to remove the drive shaft, the the rear trans cover, the oil pan, the hydromechanical assembly and then disassemble the selector shaft. It is necessary to pull it outwards. Maybe the space between transmission and car body is too narrow. I can give you the length of the selector shaft to check. The shaft seal is steel reinforced and not easy to install. Normally I have a hydraulic press but maybe you can pull it in position with a bolt and a wrench nut and a washer.
It's worth a try but maybe you are quicker with pulling the complete transmission. Talk soon, Martin