[sle39lvr]

I have posted regarding this in the past pointing at various possible culprits. However the problem still exist and I am completely clueless as I am running out of possibilities. So let me please elaborate:

Symptom:
Hard vibration/thump from rear wheels to the front of the drivetrain from 900 - 2200 rpms in all gears. It start coming in when the car gets hot, as in if I were to drive for about 30 mins in warm weather; not present when the drivetrain is cold. If I were to dive on highway with a passengers on a warm day, after 30 miles or so up hill driving in lower rpm's become unbearable. When the thump is bad, it almost feel like I am getting wheel-hop from rear wheels. Vibration is not present at all through the steering wheel.

The Car

• 2008 E90 328i
• Auto Trans
• 95K miles
• OEM 18" 162 sports wheels

Mods

• FK Coilovers
• M3 Rear Subframe Bushings
• M3 Rear Sway

Beginning
I put on the M3 rear sway and M3 rear subframe bushings Before the coil overs. The vibrations started happening right after those, but before the coil overs. This is about 15K miles ago. About 500 miles ago, my main engine mounts collapsed completely. I would imagine this vibration was the reason for them to prematurely fail. This car is driven in Florida, never seen snow or harsh conditions. The family car, never tracked or abused. Just spirited driving.

What I have tried so far

Alignment
I got various alignments from different places, everything is within specs.

Wheels
Wheels were balanced multiple times and even got the rear wheels repaired to make sure they aren't bent.

Tires
Changed the set to a new.

Engine Codes
None. Engine is running well and well maintained.

Engine Mounts
These collapsed about 500 miles ago as I mentioned above. I believe the collapsed prematurely because of this vibration. So these are replaced and the vibration still exists.

Center Axle Bearing
This is what I changed very last, because the main symptom pointed at this bearing from most of my research. I did it my self, existing bearing was not beat at all, it was in pristine conditions. I also inspected the flex disc, differential mounts, they were all in great shape. I also inpected the CV joints and moved around rear control arms, seem to be fine.

So I am running out of ideas. I do feel the car is a little jerky from switching to Drive from neutral of Reverse. This is minute, and compared to when it was brand new.

Any input will be greatly appreciated. Thanks in advance.

Has the diff or transmission fluid been changed...ever? What do the trans mounts look like?

I was getting a weird banging sensation right underneath the armrest upon acceleration at highway speeds a couple months ago. I changed a whole bunch of parts in the process of looking for broken/bad parts which might have been causing the issue "since I was in there anyway" and although I don't know *exactly* what fixed it (absolutely nothing looked worn or out of place) all I know is that the problem is now gone and the car drives better than new:
-Center axle bearing
-Redline diff fluid
-Redline D4 trans flush/new pan/reset adaptations
-335is/335i motor mounts
-E46 M3 trans mounts
-1M flex disc

Anyway, I would start with changing the diff/trans fluid since they probably need to be swapped anyway. I also would take a closer look at your axles, bearings, control arms, etc. and go from there.

[sle39lvr]

No, tranny fluid or diff fluid hasn't been changed.

[sle39lvr]

Here is the guibo. There was no play of flex when I was putting the bolts on. You guys be the judge?

[sle39lvr]

Wheel bearing?