Clunk when accelerating from a stop

G

Greg M

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Joined
Dec 29, 2018
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38
Location
Gastonia, NC
There are a couple of clunk type noises when I accelerate from a stop. When I push down or slightly pull up on the 4wd handle there is no noise. I figured that it was probably loose linkage. I had the skid plate off yesterday to install a larger transmission pan (with drain plug) and change the fluid in the transfer case. I checked the linkage and everything seemed to be solid, as in I couldn't move it. I checked the transmission mount. It looked fine and felt solid.

Any ideas?
 
Start with checking your u-joints. Then, move to checking that all the suspension bushings are in good order, and that all parts are properly torqued, including your rear sway bar.
 
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Greg M said:
Why then would the noise completely disappear if I push down on the 4wd lever? It only takes a slight bit of pressure.
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Are you doing that after the vehicle is moving or before?
 
If I hold the 4wd lever down (only slight pressure) at a stop and then step on the accelerator then there is absolutely no sound. If I accelerate from a stop without holding the lever then there are 2-3 clunks.
 
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Sounds like your transfer case linkage is out of adjustment. This happened to me after my body lift.
 
I thought it might be loose but it's not. Adjustment had crossed my mind which means switching to a cable would probably be the best solution. Although the body and frame are rust free the linkage is rusted and it doesn't look like adjustment would be possible. I wanted to get some input before I went that route because it's another $200 and it looks like it's going to be a real pain to change.

One note is that it does shift into 4wd fairly easy.
 
Greg M said:
Although the body and frame are rust free the linkage is rusted and it doesn't look like adjustment would be possible
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soak it in kroil or 50/50 mix of ATF and acetone and it will break free. if possible remove it and put it in a tray and cover with the solution for a day or so and i've seen the nastiest rusted shit break free !
 
If you want to confirm it is the linkage you could disconnect the rotator plate from the transfer case. I believe it is a 9/16 nut. Use a flathead to give a little sideways force to unseat it. Make sure it's all the way in the 2hi position and test drive it. The push pull linkage is a crappy design and you wouldn't be doing yourself a disservice if you decide to upgrade to a cable.
 
Prbably a motor mount or a trans mount. If holding the TC lever helps the sound, then take a look at the trans mount.
 
Greg M said:
If I hold the 4wd lever down (only slight pressure) at a stop and then step on the accelerator then there is absolutely no sound. If I accelerate from a stop without holding the lever then there are 2-3 clunks.
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I have the same issue, but instead of a clunk its a slight rattle.

From a complete stop, upon accelerating the quick rattle initiates and then goes away after 5-10mph..then its gone until I stop again.
Now, when I change from 2wd to 4wd HI.... the rattle disappears.

I just did a complete frame swap, and I didnt have this issue before the swap...and I can not find where the rattle is coming from.


Also to note, my wife's TJ also has the same sound I have in mine now.
 
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