knocking sound in back

paul1414 · #1 03-18-2009, 02:33 PM

I get this loud knocking sound when i over bumps or cracks in the trunk. I am not sure if its coming from underneath or in the trunk. I checked the trunk nothing is loose. I took it to mechanic he said there is a play in the trunk arm i am not sure if that will fix it. ANything else that can make sound loud knocking sound also it doesn't happen all the time. also the ride is little bumpy any suggestions or anyone else experince this

TwinsPoppa · #2 03-18-2009, 02:56 PM

Quote:

Originally Posted by paul1414

I get this loud knocking sound when i over bumps or cracks in the trunk. I am not sure if its coming from underneath or in the trunk. I checked the trunk nothing is loose. I took it to mechanic he said there is a play in the trunk arm i am not sure if that will fix it. ANything else that can make sound loud knocking sound also it doesn't happen all the time. also the ride is little bumpy any suggestions or anyone else experince this

Might be your tailgate making the sound. Do a search and you'll find different solutions. I think one of them was using felt pads.

If its not that, it might be a suspension part called swing support link. Search on that too.

Bimmer4125 · #3 03-18-2009, 03:29 PM

Check your front tie rod ends/stabilizer links. I had the same exact issue - my first post inquiring about asked about a rear end clunking sound - like a softball rolling around in the rear. The sound moved around and I could not pin it down - sometimes it was under the car sometimes the rear - I thought I was going freaking more nuts. Several suggested the front end and ta da!!! that's whatit was. Several searches here for DIY and it cost me $200.00 at the dealer. Sounds crazy, but it's true......

paul1414 · #4 03-18-2009, 06:05 PM

Mine is metal knocking sound I think from the back. Only happens when going over rough road. Took it to my mechanic he test drove and mentioned it's from play in the trunk bar ( Boomerang ) I did notice there is a play but i really don't it's causing that. Has to be something else.

paul1414 · #5 03-19-2009, 01:34 PM

Knocking sound only happens when speed is between 40 - 60KM/H not sure what else to look at. I checked everything yesterday i couldn't find anything loose either.

TwinsPoppa · #6 03-19-2009, 02:01 PM

Quote:

Originally Posted by paul1414

Mine is metal knocking sound I think from the back. Only happens when going over rough road. Took it to my mechanic he test drove and mentioned it's from play in the trunk bar ( Boomerang ) I did notice there is a play but i really don't it's causing that. Has to be something else.

What is the trunk bar (boomerang)?!

paul1414 · #7 03-19-2009, 02:26 PM

There is a play in the trunk bar ( Boomerang) left side. I don't think that can cause this knocking sound unless i'm wrong. It only happens on rough roads i can go over bumps etc no problems.

TwinsPoppa · #8 03-19-2009, 02:31 PM

Quote:

Originally Posted by paul1414

There is a play in the trunk bar ( Boomerang) left side. I don't think that can cause this knocking sound unless i'm wrong. It only happens on rough roads i can go over bumps etc no problems.

I'm sorry but by trunk bar (boomerang) do you mean the tailgate?

I'm not trying to be difficult, just trying to understand.

x555a · #9 03-19-2009, 03:04 PM

Quote:

Originally Posted by Bimmer4125

Check your front tie rod ends/stabilizer links. I had the same exact issue - my first post inquiring about asked about a rear end clunking sound - like a softball rolling around in the rear. The sound moved around and I could not pin it down - sometimes it was under the car sometimes the rear - I thought I was going freaking more nuts. Several suggested the front end and ta da!!! that's whatit was. Several searches here for DIY and it cost me $200.00 at the dealer. Sounds crazy, but it's true......

01 BMW_X5 · #10 03-19-2009, 01:55 PM

Put your SO/wife/friend back there and let them tell you on which side and vicinity they hear the knocking.