I've been trying to figure out what's going on with my TLX and I was finally able to catch it while it was making the noise that's been driving me crazy! My 2016 TLX rattles like this when the RPMs are at 600 and below 700. It also only makes the noise in Reverse or Drive - not in Park or Neutral. So I had to put the parking brake on while it was stopped but in Drive and hop out to capture it. The weather or temperature outside doesn’t matter - it does it whether it's 30 degrees outside or 70 degrees outside. It also doesn't matter if the engine is hot or cold - I can run into a store or somewhere for 5-10 minutes and it will still do it if the RPMs drop below 600 and 700.

When it makes the noise and I open the hood the noise goes away so I can’t capture it while the hood is open. A couple of shops have looked at it and of course it wouldn’t do it because the idle never went below 750 or so - and of course when they open the hood there's no sound. Someone mentioned maybe it's Chain Rattle coming from the timing chain tensioner going bad - but it sounds like it's coming from the driver's side chain. I don't hear this noise on the passenger side and I would think that if it was the tensioner that I'd hear it even when it was in Park

I've posted a link to the video here and you can hear the sound:
Does anyone have any idea to what could be causing this? I'd appreciate any help to point a mechanic in some kind of direction. The car has about 86K miles on it at the moment.

 

time to trade it for a v6

 

Yeah - I like this car though - and it's been fully paid for going on two years. I need to hang on to this one for at least another year to eighteen months so I'd like to find out what this is and get it taken care of