Imbalanced chaddering from rear end

Hey guys, after I put on my infamous stage 1 map I now have enough torque I guess particularly in first gear to create a loud chattering from the back (car is 5EAT). At the same time it creates a imbalance like something is shaking in the rear. What are the bets on? thinking maybe just rear differential bushings.

im sooo worried Think it's the carrier bearings? Maybe Ill spray the joints and all with some lithium spray and see if it does anything.

Not sure it's the same, but when I roll into the throttle in 5th gear I can fell some vibration since the dyno and 300ftlbs. But if I drop it down a gear or two it's not there.

 

I also have to move my driveline to the right a bit to keep the tmic off the clutch reservoir. It may be I need to move the vf52 to the right, also.

 

Remember I had the tranny and rear diff out last summer, I may not have everything back in the exact position it should be in.

 

I do have the whiteline bushing in the upper diff mount too.

It feels like something is flexing causing it to go imbalanced. It is more than a vibration. Doesn't seem like it wants to get worse though. I have been pretty busy and lazy to crawl under the car.

Is it possible that your spring bottoms are chattering?

 

Mine does this under load/launch, hard turn from a start or on the gas in a big sweeper. I have Swift Sport springs on Bilstein HD rears and a 3/8" spacer. Rubber around the bottom of the springs has left the building, so this is my suspicion. Could also be the rubber diff mount bushings as well allowing the diff to "squirm". Also really notice this under any driving condition when I have rear passengers, which makes me think it's the springs chattering against the bottom perch or even against themselves. Just a couple of thoughts.

hmm interesting idea . Others were suggesting that my winter tires might be creating the vibration under acceleration.