Popping in 4wd....looking for advise.

Fridge81

Member
Hey Jeep fans! I found a new noise today. Jeep has close to 120,000 miles and I recently moved up to 37s, I do have 5.13:1 gears, 1350 JE Reel front Shaft and it is a Rubicon. I don't wheel very hard. Today I came up on a climb and shifted from 2wd to 4-low. I shifted into drive from neutral with no brake and heard about 4 or more fast pops. I made the climb and heard popping a few times as I was going up. Once I got to the top I shifted back into 2wd and goosed it a little and heard no pop. I have attached a link to a video of 4-high acceleration so you all can hear this neat new noise and point me in the direction you think it may be.

Thank you all!






[video]https://protect-us.mimecast.com/s/1oUOCADXZOiVg6gs82CJE?domain=instagram.com[/video]
 

DWiggles

Caught the Bug
Hey Jeep fans! I found a new noise today. Jeep has close to 120,000 miles and I recently moved up to 37s, I do have 5.13:1 gears, 1350 JE Reel front Shaft and it is a Rubicon. I don't wheel very hard. Today I came up on a climb and shifted from 2wd to 4-low. I shifted into drive from neutral with no brake and heard about 4 or more fast pops. I made the climb and heard popping a few times as I was going up. Once I got to the top I shifted back into 2wd and goosed it a little and heard no pop. I have attached a link to a video of 4-high acceleration so you all can hear this neat new noise and point me in the direction you think it may be.

Thank you all!






[video]https://protect-us.mimecast.com/s/1oUOCADXZOiVg6gs82CJE?domain=instagram.com[/video]

What axle shafts? Sounds kinda like a bad U-Joint? Is the 1350 driveline new? Grease-able joints?
 

Fridge81

Member
What axle shafts? Sounds kinda like a bad U-Joint? Is the 1350 driveline new? Grease-able joints?

The front shafts are original stock units. I purchased the driveline new. The driveline has very few miles on it and i grease it religiously. Only the pinion u-joint and the slip yoke have grease fittings. The noise is only heard when the front end is under load. To me it sounds as if the splines on the axle shafts are stripped and can no longer grip the carrier or the hub ends, but i am not sure how logical that really is.
 

wayoflife

Administrator
Staff member
Hard to tell for sure from the video but I would start by giving your front shaft u-joints a look. That being said, it kinda sounds like you have broken teeth on your ring gear.
 

Fridge81

Member
Hard to tell for sure from the video but I would start by giving your front shaft u-joints a look. That being said, it kinda sounds like you have broken teeth on your ring gear.


Definitely hoping it is not the ring gear....Next time i get home i'll pull the cover and inspect the gear.

I was under the Jeep before i went out on Thursday and the shaft u-joints looked alright. I will give them a closer look. I think i would hear noise from them even in 2wd due to them always spinning, but being under a load vs just spinning is totally different.

Thanks for your input.
 

wayoflife

Administrator
Staff member
Run it on jackstands if you can with a helper. Sounds to me like tcase or ujoint.

U-joint should be something you can verify or rule out pretty quickly. Being that the t-case runs on a chain, I'd have to think you'd hear more than just a few pops on acceleration.

If nothing visible can be seen, I'd pop open the diff cover and give things a look there. I'd bet you'll find broken teeth.
 

wayoflife

Administrator
Staff member
Definitely hoping it is not the ring gear....Next time i get home i'll pull the cover and inspect the gear.

I was under the Jeep before i went out on Thursday and the shaft u-joints looked alright. I will give them a closer look. I think i would hear noise from them even in 2wd due to them always spinning, but being under a load vs just spinning is totally different.

Thanks for your input.

It's the load thing that gets me to think it could be broken teeth. I could be wrong though.
 

Fridge81

Member
U-joint should be something you can verify or rule out pretty quickly. Being that the t-case runs on a chain, I'd have to think you'd hear more than just a few pops on acceleration.

If nothing visible can be seen, I'll pop off the diff cover and give things a look then. I'd bet you'll find broken teeth.


I am thinking broken teeth may be it. I figured it would be a more violent sound that could be felt/heard more if it were teeth. Then again i am not exactly hitting WOT to hear the noise. I have heard front diffs go out and they seemed louder than this noise.

Have you ever experienced a chain failure in the transfer case? Does the chain only move when engaged in 4wd? I would think that over time the chain could stretch and possibly make this type of sound.
 

wayoflife

Administrator
Staff member
I am thinking broken teeth may be it. I figured it would be a more violent sound that could be felt/heard more if it were teeth. Then again i am not exactly hitting WOT to hear the noise. I have heard front diffs go out and they seemed louder than this noise.

Have you ever experienced a chain failure in the transfer case? Does the chain only move when engaged in 4wd? I would think that over time the chain could stretch and possibly make this type of sound.

Depending on how bad it is, you can drive on chipped or broken teeth for longer than you'd think. That you heard it when you did tells me that they were breaking more or just that it became pronounced under load. A cataclysmic failure is very loud and you'd know it when it happens.

A chain failure isn't common and when it happens, you're t-case will let you know.
 

Fridge81

Member
Depending on how bad it is, you can drive on chipped or broken teeth for longer than you'd think. That you heard it when you did tells me that they were breaking more or just that it became pronounced under load. A cataclysmic failure is very loud and you'd know it when it happens.

A chain failure isn't common and when it happens, you're t-case will let you know.

Okay, I will look under the cover when i get a chance and i assume i will see chipped or broken teeth. I am assuming the transfer case would let me know in the form of a broken case like what you have experienced.

When i get the chance dig into it and will report back with my findings. I work away from home, so it'll be about a week and a half before i can do anything.

Thank you very much for your help and advise.
 

jknikos

Member
Your case sounds like when I had a broken tooth on my front diff. I found it after draining my front diff fluid. I drove quite a few months like that.
 

Fridge81

Member
Well, I just pulled the cover to check out the gears. All the teeth are on the ring gear and there are no metal chunks in the bottom of the pumpkin.... the gears spin freely and quietly.... any other ideas? Run er till she shows me that is actually wrong? 20180420_165649.jpg 20180420_165641.jpg

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Fridge81

Member
Depending on how bad it is, you can drive on chipped or broken teeth for longer than you'd think. That you heard it when you did tells me that they were breaking more or just that it became pronounced under load. A cataclysmic failure is very loud and you'd know it when it happens.

A chain failure isn't common and when it happens, you're t-case will let you know.
Is it even feasible to think that splines on an axle shaft stripped some how? All u- joints look fine with zero slop.

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Fridge81

Member
A little update:

I replaced the axle u joints. Splines looked fine on the shafts and the joints on the axles weren't too bad. I drew a line on the slip yoke on the drive shaft and up on the flange and dust cover at the transfer case to see if maybe the splines the are the problem. Got everything back together, found some dirt and put it in 4 high. Hit the throttle and heard the same shitty noise...I guess it's in the transfer case. I drained the t case and the fluid was dark, but I didn't see any metal shavings. I wish someone knew what the fuck this noise was.

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