Driveshaft Flex Disc and Center Support Bearing Issue

[nleeumd]

Guys,

I have a 2011 E92 M3 6MT and just replaced the Flex Disc (Guibo) and Center Support Bearing. I was very careful with torque specs and Flex Disc installation (Arrow) orientation and reconnecting the two halves by marking each side; however, I now have a slight hum (like there's an imbalance) when driving above 70mph and gets progressively louder as I increase speed.

My questions is regarding the Center Support Bearing, when reinstalling the CSB, I did not have a press or a long threaded rod to use 36mm my socket. So instead, I just used the 36mm and just used a mallet to seat the bearing in. I felt that I had it properly seated. When spinning the CSB afterwards, it was pretty much even, with an ever so so so slight wobble when spinning it. I felt that once the CSB is mounted on the car, it wouldn't matter.

When mounting the two 13mm bolts I also had to push the center support bearing down the shaft more to align the bolts to the mounting holes, maybe 3mm. Would this cause the become unbalanced? Also, I have green differential bolt as well, not sure if I seated that in the exact same spot when installing the driveshaft back into the differential. (https://www.m3post.com/forums/showthread.php?t=1231461) Other possible scenarios? I guess I will just have to drop the exhaust again and recheck, but just wanted to see if the threaded rod with the 36mm socket should have been used to seat the CSB.

Thanks