Solved: Clunk when loading and unloading drivetrain

Hmm that doesn't sound like the hollow clunk excessive backlash causes. Know anyone with a gopro? Perhaps you can mount it under the jeep to look at different parts while driving.


There must have been a time
when we could have said no.
 
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Hmm that doesn't sound like the hollow clunk excessive backlash causes. Know anyone with a gopro? Perhaps you can mount it under the jeep to look at different parts while driving.


There must have been a time
when we could have said no.
Great idea! Its actually what I'm doing right now...Got four vids so far, no luck pinpointing it though.
 
Here is the first one I did, looking back at the t-case from the drivers side. Its in front of the T-case, next to the Tranny / bellhousing

 
Axle seems to have play in it. Other side will probably tell you more.
 
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Axle seems to have play in it. Other side will probably tell you more.
Huh? You can't even see the axle... Other side of what? I have more videos...One that shows the front axle, one that shows the rear (both driver's side) and one that shows the center of the vehicle, looking forward at the T-case and Rear DS
 
Huh? You can't even see the axle... Other side of what? I have more videos...One that shows the front axle, one that shows the rear (both driver's side) and one that shows the center of the vehicle, looking forward at the T-case and Rear DS
I'm referring to the driveshaft going up and down on the axle end. Looks like the pinion angle is increasing then decreasing. So I was assuming the axle was rotating a bit. By other side I meant turning the camera 180° towards the axle.
 
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I'm referring to the driveshaft going up and down on the axle end. Looks like the pinion angle is increasing then decreasing. So I was assuming the axle was rotating a bit. By other side I meant turning the camera 180° towards the axle.
Oh...Yeah, the jeep raises on its suspension when I accelerate and lowers when I decelerate. That is why the DS is moving like that. I have a vid facing the direction you mentioned...the camera is picking up a bunch of background noise though, so its hard to heard the clunk I'm focused on. I can upload it to Youtube...
 
If you have factory drive shaft grease the splines I had an xj that would do that until I greased it at the transfer case output shaft
 
What I noticed from that video is you hear it whenever the skid flexes. Check your trans mount at both the skid and trans ends. Also think about dropping the skid to inspect the frame.


There must have been a time
when we could have said no.
 
With all due respect, I believe checking your backlash should be your last resort. Most likely you won't hear that inside the cab, and it won't definitely sound like it is coming from under your seat. If you had that much backlash problem that you could hear it cluck, you would have other symptoms. Like if you had that much backlash that it clunked it wont be riding in the right spot and would most likely have a whine when it is not clunking. Or a bearing noise because a bad bearing could cause a backlash problem or a borked shim, but that would be floating around making more noises. It would have most likely not started after a lift either. I am not saying you don't have a back lash problem, but from the sounds of what you are describing, I would not think that is the problem and definitely wouldn't be the first place I went.

I saw on a post earlier somewhere where @Chris mentioned checking the front driveline at the skid plate. It will torque up and down with engine torque. If it is really close it can make contact.

Also I have read about exhausts hitting upper control arms after a lift sometimes. I haven't had that issue, but I have the light rears. (We have the same lift and I am still running the stock control arms too. )

I would also check the bracket for the rear track bar. Did you put a raised bar bracket on? Are all of the bolts tight?

When you are looking for clunks imagine the torque of your engine and look for something making or can make contact. If your trans mount is loose it will clunk.

If you have a swing out tire carrier that is not locked that will clunk!

Check your exhaust from the head pipe all of the way back make sure it is tight. Do the wiggle test.
 
More troubleshooting today. I wiggled the exhaust and put my camera in a bunch of other places, but I'm not seeing anything. This video is interesting though.



The T-case sure looks like its moving around a bunch. I'm going to pull the tranny mount, and give it a look see.

I think I mentioned that my axle seal was leaking? Well, I tore that apart today, and it sure seems like it was sloppy. The race has some burrs on the edge too. I'm thinking I may not have gotten the axle fully seated last time I had it out. That would cause a clunk too, I imagine. I kinda hope that is it. Would be an easy fix. I'm bringing the axle to work with me tomorrow to press the bearing and retainer on.
 
If you go to exactly 1:16 you can hear the noise at the same moment as you see the front suspension raise on the left side.
 
So...I haven't figured anything out yet. I did replace my axle seal and bearings. That wasn't it. Started going through the front suspension this evening. I have two control arm bolts that are seized in their bushings, so the rubber is "wound up" from my recent lift. They look pretty well past it at this point, so I ordered two replacements. Note: I really don't think this is it. I don't get any clunking when articulating the suspension, nor jumping up and down on the bumper (neighbors must think I'm nuts). BUT as @Alex01 pointed out and I've also noticed, its definitely co-incidental with the front suspension lifting. So...I'm going to replace them. Here is the rub...those dumb bolts do NOT want to come out. Might have to cut em...I put the fire wrench on them earlier (Mapp gas)...got a little motion out of them. I'll need to borrow some tanks if I need Oxy/Acetylene.

I suppose I should check the tranny mount...but its brand new, so I doubt that is it. This is getting frustrating. I want to drive my jeep!

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Those bushings are rough, and if they are flexing and your bolts are tight that is not good, so even if this doesn't fix your actual problem it is a problem that needs to be fixed so at least it is not a waste!
 
So...I haven't figured anything out yet. I did replace my axle seal and bearings. That wasn't it. Started going through the front suspension this evening. I have two control arm bolts that are seized in their bushings, so the rubber is "wound up" from my recent lift. They look pretty well past it at this point, so I ordered two replacements. Note: I really don't think this is it. I don't get any clunking when articulating the suspension, nor jumping up and down on the bumper (neighbors must think I'm nuts). BUT as @Alex01 pointed out and I've also noticed, its definitely co-incidental with the front suspension lifting. So...I'm going to replace them. Here is the rub...those dumb bolts do NOT want to come out. Might have to cut em...I put the fire wrench on them earlier (Mapp gas)...got a little motion out of them. I'll need to borrow some tanks if I need Oxy/Acetylene.

I suppose I should check the tranny mount...but its brand new, so I doubt that is it. This is getting frustrating. I want to drive my jeep!

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after you heat them up, try spraying them will water, acouple times.
 
I haven't seen you say this but have you heated up the bolt to get the nut off — it has heavy lock tight on it and the heat will help you break the nut free if you can get something like Areo Kroil in there it might help you out.

good luck
 
I haven't seen you say this but have you heated up the bolt to get the nut off — it has heavy lock tight on it and the heat will help you break the nut free if you can get something like Areo Kroil in there it might help you out.

good luck
I got the nuts off... The bolts themselves are seized in the bushings. I have tried heat... No luck yet.