Harsh noise during acceleration

LilHammer97

LilHammer97

TJ Enthusiast
Joined
Jun 19, 2019
Messages
213
Location
Huntingdon, TN
I went to pick my brother up and I noticed a noise that has gotten louder since I got this rubicon. I can't really describe it too well besides it sounds like its coming from underneath the center consol more towards the rear. It started getting more pronounced after going through some pretty deep mud while i was recovering my brothers stuck chevy 2500hd. Ill list the symptoms the best I can

Only happens in 2nd-6th gear.

Goes away when clutch is depressed or in neutral.

Only happens during acceleration.

Driving in 4HI seemed to quiet it down a little bit the noise was still present.

Speed/rpm seems to play a factor in how loud it is.

DOES NOT happen during deceleration.

DOES NOT have any vibration that I can feel (at the moment).

I will be checking/changing the diff, trans, and transfer case fluids while I'm doing the ZJ tie rods, core 4x4 control arms and core 4x4 track bar tomorrow (I will post a review of these components after I install them and get some good pictures). I have inspected everything I can get my hands on and I don't notice any excessive play besides the driveshafts rotating about 1/4 of an inch before "locking". (If I said that correctly) I went ahead and made a video and posted it on the YouTube


If anybody is a driveline expert here please feel free to chime in. As always ill drag @Chris into this as he knows everyone on here😛
 
I would say throw out bearing except that wouldn't go away in neutral. So the basics...have you checked fluid levels in the trans and transfer? Have you made sure nothing is stuck up under there? Some sticks, mud? Old tee shirt?
If all those have been checked then I would be leaning towards either the trans input bearing or a shift rail bearing. The fact it is less in hi range could indicate transfer bearing, but my first guess is some sort of contamination of a gearbox fluid or low level preventing good lubrication. This is assuming there was no sound prior to the water event. Good luck.
 
Goatman said:
I would say throw out bearing except that wouldn't go away in neutral. So the basics...have you checked fluid levels in the trans and transfer? Have you made sure nothing is stuck up under there? Some sticks, mud? Old tee shirt?
If all those have been checked then I would be leaning towards either the trans input bearing or a shift rail bearing. The fact it is less in hi range could indicate transfer bearing, but my first guess is some sort of contamination of a gearbox fluid or low level preventing good lubrication. This is assuming there was no sound prior to the water event. Good luck.
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Thanks man means allot cause I'm freaking out right now just reading other threads lol I wouldnt say the noise wasn't there before but maybe I just wasn't paying attention. Im gonna go the cheap route first and drain/inspect the fluid first. If it helps any both my front and rear axles are G2 44s ( the older ones with the silver diff covers) with 4.88 gears and arb air lockers.
 
In the last video there is too much play (inward movement) in the shaft that the yoke is attached to.
You might want to check to see if the nut holding the yoke onto the shaft is loose OR that shaft bearing is going bad.
 
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Okay so I've worked my way from the front to the rear. Here's some pics.

Front diff
20200707_145324.jpg

20200707_145829.jpg

20200707_145835.jpg

20200707_150233.jpg


Trans.
20200707_153636.jpg

20200707_155202.jpg


Transfer appeared to be normal for never having been serviced

Rear diff.....
20200707_155206.jpg

20200707_174600.jpg

20200707_180429.jpg

20200707_180433.jpg


I believe it was either the trans based on how many shaving was stuck on the plug. And now to the rear diff oil, I didn't know G2 axles made chocolate😂 I hope by deep cleaning the diffs and changing the fluid will help tremendously with this noise. If not im gonna narrow it down to a bearing somewhere.
 
CharlesHS said:
In the last video there is too much play (inward movement) in the shaft that the yoke is attached to.
You might want to check to see if the nut holding the yoke onto the shaft is loose OR that shaft bearing is going bad.
Click to expand...
Would you happen to know what size that would be? I'd rather try tightening it before I go digging that bearing out.
 
I do not know the size and I am out of town right now so I can't measure the one on my TJ.
More than likely one of the members can provide the size of the nut.
If the nut is loose... that is what is causing the noisy bearing.
More than likely that bearing will need to be replaced.
 
vito2772 said:
What fixed your issue OP? Seems like I have the exact same issue...Changed Rear diff fluid and that noise is still there.
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It turns out my pinion bearing had failed at some point and in turn ruined my gear set. My pinion gear ended up chipping and eating the ring gear up also. 850 dollar rebuild and the noise is gone! I will say it did drive fine for about 2 months before i could get the cash up to have it rebuilt.
 
LilHammer97 said:
It turns out my pinion bearing had failed at some point and in turn ruined my gear set. My pinion gear ended up chipping and eating the ring gear up also. 850 dollar rebuild and the noise is gone! I will say it did drive fine for about 2 months before i could get the cash up to have it rebuilt.
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Oof, I hope that isn't the case for me. Thanks for the reply. I changed the diff fluid, will change the tranny fluid next to see if it fixes it.

If not, then I'll bring it to my gear guy.
 
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vito2772 said:
Oof, I hope that isn't the case for me. Thanks for the reply. I changed the diff fluid, will change the tranny fluid next to see if it fixes it.

If not, then I'll bring it to my gear guy.
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Id just run it to your gear guy. He probably tell you exactly whats up. But be careful. I took mine to 3 "mechniks" and they all said it was either my tires or brakes.......
 
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