Actually I believe all the eta trannys were the same as the same year 533/535 but the bell housings were different so they wouldn't bolt up, with the exception of the 82 and 85 which had the removeable bellhousing. In fact I have a transmission that I took out of an 82 528e in my 85 535i. I did change the drive flange but the tranny itself was the same. You can even use a tranny out of an 80-81 E-12 and it will work. Another driveshaft possibility is out of a early 528e with the three speed auto since I used an auto driveshaft when converting my 80 633 from auto to 5-speed. Again, it was slightly different in lenght but close enough that it has been working fine for about 45 thou now. I don't know part numbers but I have definitely mixed and matched parts and I dont like breakdowns so I make sure it's right even if it isn't supposed to fit.