" Replaced the bolt and the problem appears to be fixed. The loud rumble while driving is gone, as is the strong vibrations when driving. In neutral I can feel small vibrations at ~2k, but it may be me being hyper sensitive. Going to put it all back together and do some more road driving tomorrow, as I only drove a few miles (and a couple WOT gears to be sure). "

" The nut was there, the bolt snapped in half. I just got a new bolt today and will see if that resolves the issue (BIG FINGER CROSS). "

" Setup - FBO E92, 6MT, NT05R DRs, and wavetrac LSD

Did a good 10 runs or so at the 1/4 track, one of which had a hard pop during launch. I got ittermittant wheel hop on a run, but nothing bad. On the last run, I could hear a loud hum at the too of third and into fourth gear.

When dirving home I noticed at low rpms there is a vibration and an audible him throughout the RPM band.

I've mounted the center bearing upside down on the frame on my old car (e92) and it feels like that vibration, just not as bad (but just as audible). I put the car on jack stands and can't visually see anything wrong with the rear axles, diff, or diff output.

Any ideas on how to diagnose this and what could be wrong? "