2012 JKU Crankshaft Walk?

J

jpone

Member
Just left my 2012 JK with AT at the dealer. Was making a noise that sounded like a worn out bearing or pump on the front of the engine. The tech crawled underneath and immediately commented that the crankshaft pulley was too close to the front of the engine and was rubbing causing the noise.

He told me to shut it down and leave it. He called it crankshaft walk. Im obviously not a mechanic, but it seemed pretty serious because they were talking engine rebuild or replacement.

Cant find anything on the forum about it.

If someone could comment and shed some light on this for me, would be great.

Thanks!
 
WJCO

WJCO

Meme King
It's possible. I have yet to see it on the 3.6, but maybe that tech sees a lot of them. Basically, there is a thrust washer/bearing that keeps the crankshaft within proper endplay. Maybe it's worn or damaged allowing the crank to move excessively.
 
2nd.gunman

2nd.gunman

Caught the Bug
The other common cause is the balancer delaminates allowing the outer ring to walk back into the timing case. Never seen it on a 3.6 but have on plenty of other motors.


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J

jpone

Member
News today is a bad harmonic balancer. Not sure how this would allow the crankshaft to move back and forth. I imagined the purpose of the harmonic balancer was to help balance the crankshaft as it rotates, but Im taking it as good news for the moment that the engine does not need a rebuild.

Anyone have experience with this issue and can give me some insight for the conversation wit the dealer?

Saw post from 2nd Gunman. Appreciate it.
 
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WJCO

WJCO

Meme King
jpone said:
News today is a bad harmonic balancer. Not sure how this would allow the crankshaft to move back and forth. I imagined the purpose of the harmonic balancer was to help balance the crankshaft as it rotates, but Im taking it as good news for the moment that the engine does not need a rebuild.

Anyone have experience with this issue and can give me some insight for the conversation wit the dealer?

Saw post from 2nd Gunman. Appreciate it.
Click to expand...

The balancer is a lot of times 2 pieces. It has a steel outer and a rubber inner. If the outer separated from the inner, it could have moved and hit the motor. Their original assumption that crank was walking is a common assumption, but what was really happening was the crank is fine but the balancer on the end came apart and moved, not the crank itself.

HarmonicBalancer2.jpg

failed_harmonic_balancer_34.jpg
 
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J

jpone

Member
WJCO said:
The balancer is a lot of times 2 pieces. It has a steel outer and a rubber inner. If the outer separated from the inner, it could have moved and hit the motor. Their original assumption that crank was walking is a common assumption, but what was really happening was the crank is fine but the balancer on the end came apart and moved, not the crank itself.

View attachment 262107

View attachment 262108
Click to expand...

Looks like you nailed it! Appreciate the direction here.
 
J

jpone

Member
aermotor said:
Good to know. How many miles do you have on it?
Click to expand...

88k. The telltale sign was not only the noise, but also the pulley had shifted closer to the front of the engine. There was basically a hair width between them. Normally there's a few mm gap.
 
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