hearing a crack

Holeshot

Holeshot

Banned
I own a 2012 jk, 2 door, 12 000km on it, 6 speed manual tranny.

since a couple of month, maybe 2, when I give a load to the driveline I hear a cracking sound coming from the driveline, i guess.

It happened first on 2wd, during fast stop/reverse manoeuver on pavement, and for sure it's not a bad engagement from the tranny.

And then, it happened on 4low, still while giving a load on the clutch to get out of a rut. It seems to come either from the rear driveshaft joint or from the rear differential.

I've experienced something very similar the other day. A costumer came at the shop for a similar sound on a 2012 F150. At first it seemed to come from the rear joint at the rear diff, so we changed the joint and the trouble was still there. It's the model that have 3 joints with a center bearing, so to save time, we took a driveshaft on a new truck and tried again, and still craking under load. We were able to make it happen when doing stall test (giving gas while holding strong the brakes). Finally, we opened the rear diff to inspect, still nothing unusual, no weird vibration from the cage, gears or bearings.. BUT, the cracking sound was very strong. At this point, the only option left was the pinion and/or its bearing.


Anyone experienced similar problem?
 
are you hearing a single "crack" or continuous "crackling" while in motion. before reading through your whole post, i would have said that your cv joint was going bad but, you've not only indicated that you have an aftermarket shaft, you also ran a different shaft. if you're sure it's coming from the rear end, you might need to pull the carrier to inspect the bearings.
 
I'm hearing a single crack and running OEM shafts, my driveline is completely stock. I'm only running 35's with coil spacers for now.

I did expect the need to open the diff for inspection, but since it would be under warranty, the dealer will care of this. :brows:

I was just wondering if someone else had the same problem.


On the costumer' truck I talked about above, it was quite similar. Engaged in drive, we heard one or two cracks and if we kept trying making it happen in drive, it just wouldn't do it, but if we switch from drive to reverse after every cracks, it kept doing it again and again, and I seem to have the same issue, but since we haven't worked on the truck yet, I can't tell what causes that sound.
 
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ok, if you're only hearing a single crack, i'd have to think it's suspension related - something loose and shifting. you say you're running 35's, how about you give us any and all specs on what you have installed. that'll help out a lot.
 
well it is almost stock to this point, I'm on a budget so the project is streched on couple of years :naw:

so here I go for the drivetrain :

35" duratrac tires
1.5" roughcountry wheel spacers (hub centric)
2" coil spacers w/ bumpstop extensions
tera quick disco's

everything else is not related so not important to mention.

Also, may be important to mention that I have a weird cracking coming from the cluth pivot when I press the clutch pedal, and when close to a wall, I can clearly hear it every time I press the pedal, and also hearing the throw-out bearing (I guess) moving back and forth and rolling when clutch disengaged.

I don't really know if it could be related, but as it is a part of the drivetrain, I guss it could.
 
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Holeshot said:
well it is almost stock to this point, I'm on a budget so the project is streched on couple of years :naw:

so here I go for the drivetrain :

35" duratrac tires
1.5" roughcountry wheel spacers (hub centric)
2" coil spacers w/ bumpstop extensions
tera quick disco's

everything else is not related so not important to mention.

Also, may be important to mention that I have a weird cracking coming from the cluth pivot when I press the clutch pedal, and when close to a wall, I can clearly hear it every time I press the pedal, and also hearing the throw-out bearing (I guess) moving back and forth and rolling when clutch disengaged.

I don't really know if it could be related, but as it is a part of the drivetrain, I guss it could.
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the clutch sound you here is the slave spring. it'll go bad on you soon but, not that big of a deal. make sure you have enough brake fluid as the clutch slave uses fluid from the same reservoir and you should be okay.

regarding your lift, i would check your rear links to make sure they aren't contacting anything. i would also check your rear track bar bolt to see if maybe it's making contact with your coils or even your bump stop pads.
 
my brake fluid is ok, the jk gets only 12 000km on it. And I'm used to mecanical tech's, I'm a mecanical myself but not specialized in that kind of noise ;)

I will look for loose suspension parts, and if I find nothing i will take an appointment at the dealer for the clutch and cracking sound.

Thanks for your help.
 
Holeshot said:
my brake fluid is ok, the jk gets only 12 000km on it. And I'm used to mecanical tech's, I'm a mecanical myself but not specialized in that kind of noise ;)

I will look for loose suspension parts, and if I find nothing i will take an appointment at the dealer for the clutch and cracking sound.

Thanks for your help.
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Check that rear track bar bolt.

My now EX-girlfriend's jeep would make that same sound..... turned out the trackbar bolt that affixes the trackbar to the rear axle was GONE!!!!!!
 
ok, I made an overall inspection, tightened the wheel spacers, cheked with a prybar to see any loose suspension parts, and everything is fine. My rear links are not rubbing anywhere either.
 
Holeshot said:
ok, I made an overall inspection, tightened the wheel spacers, cheked with a prybar to see any loose suspension parts, and everything is fine. My rear links are not rubbing anywhere either.
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how about your rear track bar, did you inspect it?
 
Yeap, and there is no sign of loose bolt, the paint around the bolts is like new, I tried to make it move with the prybar and it seems to be just fine... It smells like I gonna have to bring it to the dealer :thinking:
 
Ok, had my appointment last week, and they found nothing. This morning I was reading over jk-forum and just fell on this thread (see link below), which could be a part of my cracking noise I guess. I also read that I should tighten my trackbars bolts when the jeep is on its wheels, and not on the lift, which I didn't know.

http://www.jk-forum.com/jk-talk-26/...ock-track-bar-lower-control-arm-bolts-210051/

My bud has a weird DW, and also think this could be his problem since the dealer haven't found the problem yet.

So now, next week I'm going to change at least my trackbar bolts and tighten properly. Don't know if I should replace de lower control arms bolt right now. I know I really should as it will save me from having trouble with this later, but If I do i'm gonna have to do an alignment, and its something I was not expecting in my budget lol.
 
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Holeshot said:
Ok, had my appointment last week, and they found nothing. This morning I was reading over jk-forum and just fell on this thread (see link below), which could be a part of my cracking noise I guess. I also read that I should tighten my trackbars bolts when the jeep is on its wheels, and not on the lift, which I didn't know.

http://www.jk-forum.com/jk-talk-26/...ock-track-bar-lower-control-arm-bolts-210051/

So now, next week I'm going to change at least my trackbar bolts and tighten properly. Don't know if I should replace de lower control arms bolt right now. I know I really should as it will save me from having trouble with this later, but If I do i'm gonna have to do an alignment, and its something I was not expecting in my budget lol.
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nah, i'm not buying it especially being that your issue is coming from the rear. i should note that even the thread above is just a lot of FUD (fear, uncertainty and doubt). so long as you have your bolts tightend to torque spec, this shouldn't be an issue and there is no need to replace them. a single cracking sound like you are hearing is almost always a suspension related noise and one that is caused by something shifting around or catching. have you checked your sway bar bolts to see if they might be catching on the brake lines or there about? after installing your lift, your axle will have shifted over a bit and that would have pulled your sway bar over the driver side. even if you installed a relocation bracket, the sway bar could still be out of center and cause this problem or, if you got less lift due to weight, your axle would be off the other way due to the bracket being too tall. either way, i would check that as it is something i have seen before.

regarding the tightening of your track bar, yes, it and all your joints should be tightend with your jeep on the ground as to prevent preload on your factory bonded rubber bushings. this is not needed if you have something like a johnny joint.

My bud has a weird DW, and also think this could be his problem since the dealer haven't found the problem yet.
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i have yet to hear of a dealership ever finding or fixing death wobble. you need to read through this post and do the following checks:

http://wayalife.com/showthread.php?...s-What-it-isn-t-and-What-You-Can-Do-to-Fix-it
 
yeah I know about death wobble, had some on my old TJ with worn out trackbar bushing.

Forgot to mention that for my noise, I heard it again last week after I picked it from the dealer. I tried to make it happen again to find out where it could come from. I found a nice washout, jumped in, and tried several things to make it happen. The only time I heard it, is when it stalled under load, held the brakes, then it cracked when I started and it seemed to come from the front end this time. Like if it was a motor support bushing or something.

Needless to say that I don't fking know where to look at now :thinking: Someday it seem to come from the back, the other day I felt it in the shifter, then hear it from the front...

Anyways, the service manager at the dealer heard it last week when doing the road test and she (yes it's women xD) told me they gonna give it a look when I'll bring it back for my heater core replacement.
 
unless you can set it up so that you can hear it outside, it's always hard to find noises inside your jeep as sound has a way of traveling through the drive train and body.
 
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