Both trailer and truck are perfectly level. 82000 miles with new front ball joints. Tongue weight is no where near the limit, and the noise only happens when the front suspension is slightly unloaded.

When towing (especially uphill) when I hit larger expansion joints there is the initial tire sound of the front tires hitting the joint and then a clunk rattle coming from directly under the dash in the footwell area. Sounds like someone is hitting the firewall area with a hammer 3-4 times immediately after a bump.

Hopefully someone here has had this symptom before. Any ideas of what this might be? Body mounts? Maybe the front struts hitting a limit?

Thanks in advance!

 

I would suspect your exhaust down pipe is touching.

 

The downpipe is on the other side of the motor. The clunking noise is coming directly from the drivers side pedal area.

 

Automatic or manual?

 

Automatic

 

When you installed the new exhaust if you dropped the transmission support to get the down pipe out it might not be fully tight allowing the transmission to touch the side of tunnel under load or the transmission mount might not be tight enough causing the same thing.

 

Thanks busboy - the transmission mount was never loosened to put the exhaust on.

This noise only happens when the front end is "light." Do you know of any body mounts in that specific area or even suspension bits that could make a clattering noise like that?

 

I know you said "new ball joints" but they could be bad, bad or worn ball joints make a rattling sound when going over bumps. How about the steering damper? Might also want to check the tightness of the front shocks, my last truck one shock wasn't tight from new and caused a rattle when going over bumps.

 

Checked the ball joints and steering damper was just done by the ***********.

Next step is to check the strut mounts - hopefully I find the top one loose!