Loud clunking noise

[connor0770]

Ok guys I got a question for you. I'm getting this really weird and random clunking noise. Basically when I turn my Jeep on it clunks (like my exhaust is banging against something) then it doesn't do it. Once I put it in drive or reverse it makes a metal on metal noise. The best way I can describe it is, it sounds like my driveshaft is spinning freely and has a bad u joint. I really hope it's my exhaust but it really only does this in drive and reverse (when stopped). And when I turn the jeep off it makes the same noise as start up and the keep barely shakes (feels like the exhaust is shaking). What should I check first? Could it possibly be my flex plate loose?

Or could it be my CV in the DS? I get a grinding noise when im on the gas at 50+. It's only when I'm accelerating, not coasting. (so if it's the DS wouldn't it always make the noise since its spinning at the same rate?)

Thanks guys!

 

[Mike1331]

To hard to say, post up a vid of offending noise. Sound anything like mine did on the con?

 

[blondejoncherokee]

check trackbar bushings/tre and all bolt mounts
check control arm bushings
check all steering and suspension bolts
check exhaust mounts and check brake caliper bolts
check motor mounts
check u joints

 

[connor0770]

whats the best way to see if the motor mounts are shot? i can see em and the bushings dont look too bad.. theres a small crack in each

also my rear trac bar is stock... think that would make a difference? Really dont want to spend the money on a new one just to go to a 4 link here in a year.

control arms are JJ's all around.

I do need new brakes.. i guess that could be the problem.. the caliper bolts i still need to check, and they would make noise just coasting right?

u-joints im gonna take the DS off tomorrow morning and inspect.

 

[XJensen]

The motor mounts are easy to take out and they may not look bad while installed but could look worse once they are pulled out.

I thought mine were fine, until I pulled them to put in a set of Brown Dog Mounts. The rubber was very worn on the stock mounts and very depressed. This didn't cause any noises in my jeep though, not saying it couldn't though.

 

[Tenny]

1. New Motor mounts.
2. Remove rear track bar

 

[connor0770]

ok i think ill order some brown dogs then here in the next week or so. Did you guys go with Poly or rubber?

 

[Mike1331]

id go with rubber on a dd xj. but your super cool with a tj and all so the box frame will do a better job dampening things...so poly might work out fine and last longer.

 

[XJensen]

I have the rubber ones, they work great and you can always swap out bushings.

 

[connor0770]

Mike wouldn't your sweet unibody flex help absorb the added vibes of a poly bushing? Hahaha. I think I might go with rubber. If my stock rubber can last from 97 to 2012 I think browndog rubber can last just as long.

 

[Mike1331]

Mike wouldn't your sweet unibody flex help absorb the added vibes of a poly bushing? Hahaha. I think I might go with rubber. If my stock rubber can last from 97 to 2012 I think browndog rubber can last just as long.

Has it been wheeling trails like the con and bronco canyon since 97? I put new rubber ones in two years ago and they're cracked already... Those are stock units though. I'm sure brown dog units will last longer.

 

[connor0770]

Has it been wheeling trails like the con and bronco canyon since 97? I put new rubber ones in two years ago and they're cracked already... Those are stock units though. I'm sure brown dog units will last longer.

i was waiting for you to say that... The poly's are cheaper to and eventually its gonna be a wheeling only rig, so im not too worried about vibes.

 

[connor0770]

well crap.. this noise sounds internal.. I had it in park and it was making the noise. I crawled under the jeep and traced the sound to the engine block.. Sounds like something broke or something is lose rattling around.. I dont even know where to begin

 

[blondejoncherokee]

can you post a you tube vid of the noise?
motor mounts are usually visual. turn on the jeep, have it in park, have a buddy rev it up and watch the mounts. if the engine stays put and the mounts dont move around you are good. i had a friend who cracked an exhaust manifold with 2 broken motor mounts, his engine was tweaking all over when he revved.
have the same buddy turn the steering wheel back and forth and look for pay in control arms, trackbar, tranny mount, etc

if you dont have the bucks right now i think stock mounts are like 6$ each on rockauto, the tranny mounts are cheap on there too. could help rule that out.

 

[Mike1331]

well crap.. this noise sounds internal.. I had it in park and it was making the noise. I crawled under the jeep and traced the sound to the engine block.. Sounds like something broke or something is lose rattling around.. I dont even know where to begin

pull the oil pan, maybe oil pump bolts backed out or something. i hate pulling the pan, i'm pulling mine tonight.

 

[connor0770]

ok so im almost positive its in my exhaust. Sounds like i got crap in the pipes... only at idle it makes the noise and only in drive/reverse with the breaks on... why? i dont know..

I would love to pull my pan but its my daily driver (SUCKS)... im looking for something i can DD. Might be trading the dirtbike for a dual sport.

 

[#S194]

Well, if it's in the exhaust i would guess its the catalytic converter. I had a noise coming out of my exhaust and narrowed it down to the converter. Cut it out and found the honeycomb baffle inside had broken loose and was over half plugged.

 

[connor0770]

Well, if it's in the exhaust i would guess its the catalytic converter. I had a noise coming out of my exhaust and narrowed it down to the converter. Cut it out and found the honeycomb baffle inside had broken loose and was over half plugged.

When i do this should i go high flow cat? And should i do new exhaust from the manifold to the muffler? I want to get a long circle muffler so i have room under the Jeep for when i put a new skid on and 4 link it.

i dont know crap about exhaust!

 

[Jeep450r]

When I smogged my heep, I asked the guy about cats.

Magnaflow and other generic cheap high flow cats tend to go bad within about 2 years.. just about in time for re-smogging. You might be able to get a little more out of it.. depends on how much you drive, how you drive, and who put it together lol.

Thats just his opinion. Other than that, I dont know much else lol

 

[Mike1331]

My buddy has one for sale here in folsom.

2004 crf450- he has rim/tire set ups for both the road and dirt

Not sure what he's asking but its a sweet bike. Let me know if you want his contact info.