[mineral.f32]

Hello,

I have a 435i 2016 with 67k miles. I recently installed a wagner catless downpipe. I also have a resonator delete.

After driving the car for a while like this, now when I start my car up from cold there is vibration and noise when shifting the car from P to D. The vibration or humming stays when the car is sitting in drive at idle and when switched back to park it goes away. Then comes back again when switched into D. The vibration completely goes away when I reach a higher speed but is very noticeable when the car is not moving in drive.. Also after the car warms up a bit the vibration is completely gone even when in drive and at a stand still.

I have been doing a few hours of reading on this site and found some info on motor mounts but I dont think thats the issue given it goes away when the car is warmed up.

I also figured it could be the downpipe being installed incorrectly as I had a shop do it, but once again the sound is only after a cold start when shifting into drive from a standstill.

I also read into the 8 speed auto transmission as the fact that I only hear the noise when switching from P to D at idle tells me it could be something wrong there.

Has anyone experienced this before or have any advice? Its making me very nervous. This just started happening yesterday after my car sat at work all day. It also happened this morning. I have attached a link to a video where you can clearly hear the noise when I change from either P to D or N to D. I show it twice in the video. The noise goes away after a couple seconds each time.


https://youtube.com/shorts/4OcbE_z3tX0?feature=share

Thank you in advance for any tips!

[USC_MTBR]

Are there any codes other then the ones you'd expect from the down pipe? I wonder if the shop did something wonky with the bank 1 o2 sensor which is messing with the fuel mixture. Pretty sure that would persist after it warms up though, but it could be a couple things compiling together.

[mineral.f32]

Originally Posted by USC_MTBR

Are there any codes other then the ones you'd expect from the down pipe? I wonder if the shop did something wonky with the bank 1 o2 sensor which is messing with the fuel mixture. Pretty sure that would persist after it warms up though, but it could be a couple things compiling together.

There are no other codes other than the catalyst code. What makes me think its the tranny is that it only happens when shifting into Drive. As you see in the video the noise goes away very quickly. Also, the car feels like it drives perfectly, everything shifts quickly and there is no loss of power that I can notice.

Very strange….

[mineral.f32]

Bumping.. this morning it happened again just as I started the car and before I even took it out of park. Also it hesitated to start up.