New cluck thud noise in all gears (1 Viewer)

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Nov 6, 2017
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Location
Eagle, CO
Hi all. I wanted to see if anyone can please provide me with direction of source of this noise might be.

1980 FJ43. In last 5 days I drove it 1100miles, no issues of any kind. It was super good on HWY and back roads. Speed was up to 75mph, no issues.

Yesterday I was taking kids to school, and it started to make this clunky noise.

In 1st gear starts immediately .
In 2nd, after I reach slightly higher speed from what 1st gear can give.
In 3rd, after going faster that 2nd gear.
In 4th, above 3rd gear speed.

With each higher gear, noise "builds up" and then shift time arrives.

Sort of each gear has to pass son its shifting speed for noise to continue.

I have recorded it, sound bit is added. You can hear shifting points, and clunking to follow.

I have no other issues, shifts very smooth, clutch engages what I think is perfect.
H2/H4/L2 all engage perfect.
There is no grinding that I can feel, via touching shifter, or H2/H$ shifter. No vibration other that normal car shake.

Cluck is present in all H2/H4/L2 drive mods.
It is not present while in gear but clutch is pressed.
Also not present in neutral, rolling down hill.

Only when drive is engaged and pulling forward. Did not her it in reverse.


Sound bit is:

http://regjo.com/FJ43.mp3

http://regjo.com/FJ43.mp3

Any help is appreciated.

I did search older posts, and found possible check point, CONE shaped cover. Will try to locate it and re tighten if needed.
 
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I'm no expert... Is it possible your TC shifter isn't fully engaged?

Thank you, Could you clarify what that exactly means? I don’t want to assume I have already checked or have a same thing in mind as you do. If you could let me know what the TC shifter is I will confirm on my end. Thanks for your time.
 
Are you sure it's not a u joint issue?
Thank you, I cannot eliminate U joint possibility. If this helps, when the car reaches normal operating temperature, the noise goes away. All gears shift like they used to however the noise is completely gone. I do give it a few minutes to warm up in general but after about 10 minutes of driving it seems to go away. I had a chance to test that as I was posting this note.
 
Listened to audio. It sounds like the frequency (timing) of the knock is not the same as rpms, e.g. the knock does not seem to increase or decrease with rpm. There is a startup timing for the knock related to rpm and it’s different (delayed) for 4th gear. Can you tell where the noise is coming from?
Questions for experts:
If drive train related then what in the drive train has the same operating frequency regardless of rpm? And what does operating temp have to do with this? Is this rather something vacuum related?
 
Thank you, Could you clarify what that exactly means? I don’t want to assume I have already checked or have a same thing in mind as you do. If you could let me know what the TC shifter is I will confirm on my end. Thanks for your time.


I assume you have a 4-spd shifter, in the floor and a transfer case shifter next to it... I meant... Make sure your transfer case is not "between gears"... I.e. Fully in 2Hi, fully in 4Hi, etc.
 
Listened to audio. It sounds like the frequency (timing) of the knock is not the same as rpms, e.g. the knock does not seem to increase or decrease with rpm. There is a startup timing for the knock related to rpm and it’s different (delayed) for 4th gear. Can you tell where the noise is coming from?
Questions for experts:
If drive train related then what in the drive train has the same operating frequency regardless of rpm? And what does operating temp have to do with this? Is this rather something vacuum related?



Thank you. As far as where noise is coming from. My best guess right now is inferno to stick shift, somewhere there. My audio recorder was laying in-between stick shift and transfer case stick, and recording.
It does not sound like it is from driver nor passenger side over all, but "dead" center.
 
It has a hollow sound to me, so I'm guessing driveshaft or U-joint related. I'd double check both driveshafts.
 
It has a hollow sound to me, so I'm guessing driveshaft or U-joint related. I'd double check both driveshafts.


Thank you, I will see what it’s involved to check those items. If it’s not doable in a small home garage, I will be looking for a mechanic around my area. I’ll see what the forum has maybe some how-to, or if you have a pointer for a pre-written links let me know if you would thank you
 
Thank you, I will see what it’s involved to check those items. If it’s not doable in a small home garage, I will be looking for a mechanic around my area. I’ll see what the forum has maybe some how-to, or if you have a pointer for a pre-written links let me know if you would thank you

By the sound, simply crawling under and grabbing the shafts and trying to move them in all directions might be all you need to do. Also, a good visual inspection of the fasteners.
 
By the sound, simply crawling under and grabbing the shafts and trying to move them in all directions might be all you need to do. Also, a good visual inspection of the fasteners.
Thank you very much. I have upcoming holiday off so it will be spent underneath the car checking whatever is there to check shaking rattling pulling stuff apart. Once again thank you all for all your knowledge and willingness to share.
 
The sound does not speed up as the vehicle speeds up. This to me rules out gears, driveshaft wheels and anything else that rotates. Look around for a loose hose wire or body part dangling that may be buffeted by wind or vehicle movement.
 
I think you should take it to a shop that has mechanical ears. I use them all the time to find mystery noises and they take out a lot of the guess work. My best guess is that you have a bearing issue somewhere and it quiets down once it gets hot. You will need to find the bearing before you will be able to address it.
 
Another new thread reminded me of a noise I have occasionally. What is the outside temperature where you’re at? When it’s below freezing my speedo cable will make noise until the vehicle is warmed up, not necessarily or apparently speed related. The speedometer needle will “bounce” somewhat as well. Figured it was moisture in the cable. It’s a replacement cable about 8 yrs old now for the missing cable when I became the new PO for the rig. Just another thought.
 
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Middlecllf reminded me of the Fiat I had that the speedo cable would click except you say it doesn't make the noise while coasting in neutral. the cable should still turn while coasting. I take it the noise is only when the vehicle is moving. Have you gotten any idea of where the noise is coming from? I am still thinking it is something bumping the body or frame. Possibly something is rubbing against a rotating part and flipping against something else. I am just taking shots in the dark here. You are going to have to let one of those girls of yours drive while you crawl around listening.
 
An easy thing to check is this nut. If not staked properly this nut will back off. Wich allows the input gear, spacers and bearing to slide back and fourth on the trans output shaft. Makes clunking noises starting/stoping/shifting or on the throttle and letting off and some strange gear noises at times.
IMG_2943.JPG
Behind this cover.
IMG_2944.JPG
 
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An easy thing to check is this nut. If not staked properly this nut will back off. Wich allows the input gear, spacers and bearing to slide back and fourth on the trans output shaft. Makes clunking noises starting/stoping/shifting or on the throttle and letting off and some strange gear noises at times.View attachment 1570764Behind this cover. View attachment 1570765
Thank you, that cone shaped cover is on my list of items to check. Thank you for visual help.
 
Seven or eight years ago we had a big snow that lasted for a week. I was doing a lot of driving with chains on the back for most of those days. I started hearing a low intermittent knock and thought it was a loose chain. After I removed the chains the noise was still there. It turned out to be several of the bolts on the rear axle ring gear were loose and hitting the housing. Put an outward dent in the cover and rounded the heads on a couple of the bolts.
 

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