[gunclap]

I noticed that when I go over sharp bumps, I can hear a plasticky type of thud/rattle sound coming from below the gas pedal area. The thud is heavy...kind of like if my front sway bar is loose and it resonates when hitting a sharp bump (not a metal sound). When I go over rolling bumps, there's no sound. Anyone have this issue? I haven't had the chance to check the underside, but will do it this week. I had noticed the sound months ago (April) after I went off roading at Gorman, but the sound is more pronounced now. I had noticed it after July 4th weekend when I took it to White Mountain Peak (dirt road all the way up 11,000 feet), then to Titus Canyon Road in Death Valley. A couple of weeks after that, I took it up Rowher Trail in Santa Clarita. The car drives straight and there's no play on the steering wheel when it hits a bump.

 

[bwbike]

The first thing I would check is if there is a stick or rock that lodged up in between the engine/trans & skid plate.

 

[gunclap]

I wanted to follow through with this threat - some may have the same annoyance. I changed oil two days ago and I had a chance to go under the car and try to figure where the sound is coming from.

Imagine going over a sharp bump on the road and the exhaust moves up and down creating a resounding, heavy, thud - it's a hard plastic/rubber kind of sound, like the sound is coming from that rubber piece holding the exhaust (see video). Again, this sound recreates over sharp bumps - rolling bumps are ok. The exhaust system has never been hit. No markings and no awkward bends.

Any thoughts?

https://youtu.be/MRauNvKL9tc

 

[raz-0]

Well, you moving it very little makes a loud metallic bang before seriously using up the range of movement the rubber bushing is capable of. So that would lead me to suspect that isn't the source of the problem.

The only thing I have encountered that presents under the exact conditions you stated was the rear license plate and frame whacking into the lift gate due to only having two screws. That pretty much sounds like it comes from low down in the cargo area.

 

[Rskitall]

I would just take it in to the dealership one of those hangers might be broken

 

[fmunk]

Loose full size spare or tool kit?

 

[syzygy]

The noise probably sounds different inside the car. I do not believe your exhaust should do that.

 

[White_THawk]

My Trailhawk does the same thing. It wasn't too long after I had the car as well. I've been to lazy to look at it in depth. I do a good amount a offroading though, but it started happening after some easy offroading. Nothing hitting under the car.

I assume its the exhaust/cat banging around due to the rubber hangers being broken in. The heat/vibration has soften/loosened up the rubber hangers allowing for the extra movement.

Or it could be a hanger broke or a rubber hanger came off. I don't know for sure... too lazy lately.

 

[gunclap]

My Trailhawk does the same thing. It wasn't too long after I had the car as well. I've been to lazy to look at it in depth. I do a good amount a offroading though, but it started happening after some easy offroading. Nothing hitting under the car.

I assume its the exhaust/cat banging around due to the rubber hangers being broken in. The heat/vibration has soften/loosened up the rubber hangers allowing for the extra movement.

Or it could be a hanger broke or a rubber hanger came off. I don't know for sure... too lazy lately.

I'm glad I'm not alone on this. I assume it's the rubber hangers allowing more movement. It's not a metal sound, more rubbery sound. I go off-road, as well, and I noticed it after the 2nd or 3rd time on easy dirt.

 

[Newcastle Scott]

yes its the exhaust flopping around in the hangers. The one in front of the Cat Converter mostly the problem.

My Trailhawk made a banging noise while offroading since I bought it in April.

Jeep really should have added an additional hanger or put firmer/heavy duty ones in. There is like a 6 foot section of steel pipe and Cat Converter that is unsupported.

I took it to the dealer but they don't think its a problem. Test driving around on paved roads it is fine.

I finally fixed my problem by sticking rubber filler strips in the voids of the hangers thereby taking away the ability of the exhaust to flop around a inch or so while traveling over the bumps.

I used some 1/2 thick rubber strips I found laying around the garage. I think its some high density rubber weather stripping for insulting doors and windows I got at the Home Depot a long time ago.

 

[gunclap]

Thanks for the info. I'm going to try this over the weekend.