Need help with grinding noise JKU 3.6 2013

rich67

rich67

Caught the Bug
So recently I developed a really bad metallic grinding noise that at first sounded like it was coming from the gearbox (I have a 6sp), but after some investigation led me to underneath the Jeep in the area of the crankshaft pulley (?). The noise comes from that region and into the area of the crankshaft. I uploaded a video of it to youtube:
I had the clutch replaced and the noise went away a little. But I still hear the noise (not as bad as in the video), and it is a constant, not- RPM- dependent noise. When you turn the motor off, there is a slight grinding noise as if something is rubbing or a bearing is failing as the motor winds off, and there is also the same noise on startup.
I have had the engine ticking for about 40k miles, and am worried the crankshaft or something else is failing. About 8 months ago the engine was throwing "cylinder misfire" codes, which I cleared out and they didn't repeat after a couple times.
So bear in mind that after the clutch job the noise is significantly less than on the Youtube video I posted, but it is still there, noticeable more at idle at a light and upon engine startup and shut down. Any help would be appreciated so I can go into my mechanic and not look like a complete moron.
 
I am hoping that's all it is. I'll mess with it this weekend and see if I can isolate it.
 
So I ended up spraying some lubricant onto the crankshaft pulley and the noise is significantly better, so it looks like that’s my issue. I also found a loose exhaust coupling that was causing all kinds of other rattles. So my Jeep is once again relatively quiet- probably quieter than the first day I bought it!
 
Going crazy with this noise. So it came back again and is worse than ever. I disconnected the belt and it is not the crankshaft pulley. I isolated the worst of it to under the drivers side (see image). I’ve searched for diagrams of the Pentastar and can’t figure out what’s in this area of the engine. Can anyone advise what this part is and what possibly could be causing the noise coming from this area? Jeep runs amazing otherwise, no vibrations, no difficulty shifting (new clutch is great) and all fluids are good- no obvious leaks. IMG_5835.jpegThis image is under the drivers side, right side of the pic is toward the back of the Jeep. Nose appears to be coming from this canister and the area around it, and you can see a lot of residual oil around the entire area all the way to the passenger side.
 
rich67 said:
Going crazy with this noise. So it came back again and is worse than ever. I disconnected the belt and it is not the crankshaft pulley. I isolated the worst of it to under the drivers side (see image). I’ve searched for diagrams of the Pentastar and can’t figure out what’s in this area of the engine. Can anyone advise what this part is and what possibly could be causing the noise coming from this area? Jeep runs amazing otherwise, no vibrations, no difficulty shifting (new clutch is great) and all fluids are good- no obvious leaks. View attachment 401183This image is under the drivers side, right side of the pic is toward the back of the Jeep. Nose appears to be coming from this canister and the area around it, and you can see a lot of residual oil around the entire area all the way to the passenger side.
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when was the last time you changed out the front hubs? NVM, went back to your original video post

Also, get an automotive stethoscope, they're cheap and great for isolating noises if you can safely check while the Jeep is running.
 
This noise is so loud, I think I'd go deaf using a stethoscope...lol. It literally got my ears ringing while i was underneath it.
 
rich67 said:
Going crazy with this noise. So it came back again and is worse than ever. I disconnected the belt and it is not the crankshaft pulley. I isolated the worst of it to under the drivers side (see image). I’ve searched for diagrams of the Pentastar and can’t figure out what’s in this area of the engine. Can anyone advise what this part is and what possibly could be causing the noise coming from this area? Jeep runs amazing otherwise, no vibrations, no difficulty shifting (new clutch is great) and all fluids are good- no obvious leaks. View attachment 401183This image is under the drivers side, right side of the pic is toward the back of the Jeep. Nose appears to be coming from this canister and the area around it, and you can see a lot of residual oil around the entire area all the way to the passenger side.
Click to expand...
that looks like the starter, and would make a horrible grinding noise if it's stuck or not completely disengaging.

whack it with a hammer and see if it helps, old school move to get it to disengage.
 
rich67 said:
. Can anyone advise what this part is and what possibly could be causing the noise coming from this area? View attachment 401183This image is under the drivers side, right side of the pic is toward the back of the Jeep.
Click to expand...
jeeeep said:
that looks like the starter, and would make a horrible grinding noise if it's stuck or not completely disengaging.

whack it with a hammer and see if it helps, old school move to get it to disengage.
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Agreed. Starter motor.

And agreed, it's hammer time. Don't whack it hard enough to crack the casing, but hard enough where the guts inside move.
 
That noise in my JK was the throw out bearing retainer. The JK clutch is notorious for making all sorts of grinding and clanking noises. Centerforce has done a lot of research & development to find out what’s making all that racket and how to eliminate it. They’ve got a couple of videos out that are quite educational.
 
GP NOIR said:
That noise in my JK was the throw out bearing retainer. The JK clutch is notorious for making all sorts of grinding and clanking noises. Centerforce has done a lot of research & development to find out what’s making all that racket and how to eliminate it. They’ve got a couple of videos out that are quite educational.
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I thought that was the case too. I recently had the entire clutch replaced and the noise was there before the replacement and it’s still there. The starter theory makes sense to me because about a month prior to this happening I noticed sluggish starts and occasional non-starts I thought was battery related.
 
Considering the symptoms you’re describing, combined with the fact the grinding noise is constant, it’s past time to replace the starter. If the grinding noise IS from the starter, it means the starter gear isn’t retracting.

Still, don’t discount it being something in the clutch assembly. Unless all parts, including the retainer, arm, clip, pivot ball and so on, were replaced and the bearing retainer properly greased, the clutch will continue to rattle and grind.
 
138k miles, just to be on the safe side I will replace the starter and see if that resolves the issue. If not, back to the drawing board I go.
 
rich67 said:
This forum is the best. You guys are awesome. Pulled the starter, bendix was not disengaging (hammer test was negative- I couldn't get enough leverage to give it some good taps). Flywheel was good. Starter replaced and the Jeep is as quiet as it could be..lol.
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I’m glad for you that I was wrong about the clutch assembly
 
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