2018 Jlu sport lsd question

Stlrfan152

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Ive seen the post about the issues people are having with the limited slip diffs. My jeep makes a weird noise around 20 mph, so i jacked up the jeep to spin the tires. Just wondering if this noise is normal?

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Ive seen the post about the issues people are having with the limited slip diffs. My jeep makes a weird noise around 20 mph, so i jacked up the jeep to spin the tires. Just wondering if this noise is normal?

Sounds like the clutch went bad or have let chunks into the bearings. I’d take it to the dealer!
 

txj2go

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Need more information about the conditions of this test.
First- front tire or rear tire?
Second- did you jack up one side or both sides?
Third- was the car in gear or in park?

Rear tires- the 2 tires and the driveshaft are connected together by the spider gears (which would be backed up by the limited slip clutches). One tire in the air, one tire on the ground, transmission in gear/park- the tire up in the air shouldn't turn at all.

Both tires in the air and transmission in gear/park and tire on one side would not want to turn without applying a lot of torque to overcome the clutches. With no limited slip then the spider gears come into play and one tire turns one direction, the other tire turns the other direction. If it is making that noise then something wrong with the spider gears.

Both tires in the air and transmission not in gear/park, if the limited slip is working then both tires turn one direction and the driveshaft turns. If it makes that sound then the ring gear or pinion is damaged.

If you are jacking up the front tires then it is a different story because in 4 high everything is disconnected and tires should rotate with no sound/resistance.
 
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Stlrfan152

Stlrfan152

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Thanks for the response. This was the driver side of the rear axel with both tires off the ground and the wheels spinning opposite direction. I have a m/t but the rear spun the same in first gear or neutral. Some post on the forum say the wheels will spin opposite even with a lsd on the JL.
 

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Need more information about the conditions of this test.
First- front tire or rear tire?
Second- did you jack up one side or both sides?
Third- was the car in gear or in park?

Rear tires- the 2 tires and the driveshaft are connected together by the spider gears (which would be backed up by the limited slip clutches). One tire in the air, one tire on the ground, transmission in gear/park- the tire up in the air shouldn't turn at all.

Both tires in the air and transmission in gear/park and tire on one side would not want to turn without applying a lot of torque to overcome the clutches. With no limited slip then the spider gears come into play and one tire turns one direction, the other tire turns the other direction. If it is making that noise then something wrong with the spider gears.

Both tires in the air and transmission not in gear/park, if the limited slip is working then both tires turn one direction and the driveshaft turns. If it makes that sound then the ring gear or pinion is damaged.

If you are jacking up the front tires then it is a different story because in 4 high everything is disconnected and tires should rotate with no sound/resistance.
Did you mean, for the front axle, that in 2 WD (not 4H) the FAD disconnects the axle? I believe the FAD locks in 4H and L. I may be misunderstanding your post.
 

txj2go

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Thanks for the response. This was the driver side of the rear axel with both tires off the ground and the wheels spinning opposite direction. I have a m/t but the rear spun the same in first gear or neutral. Some post on the forum say the wheels will spin opposite even with a lsd on the JL.
The spider gears cause the tires to rotate in opposite directions when the driveshaft is not turning. With LSD the spider gears are still there, the only thing that changes is that the clutch packs provide resistance for the spider gears to turn. If you have lockers then instead of clutch packs to keep the spider gears from turning, there is a hard lock that engages.

Did you mean, for the front axle, that in 2 WD (not 4H) the FAD disconnects the axle? I believe the FAD locks in 4H and L. I may be misunderstanding your post.
I wasn't thinking and got my words confused- in two wheel drive with the FAD disconnecting the shaft on one side... that one wheel should turn freely with nothing else internal rotating to cause noise, the other tire rotates the spider gears which could cause noise if they are damaged, and this system precludes having LSD in the front axle.
 
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Stlrfan152

Stlrfan152

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The spider gears cause the tires to rotate in opposite directions when the driveshaft is not turning. With LSD the spider gears are still there, the only thing that changes is that the clutch packs provide resistance for the spider gears to turn. If you have lockers then instead of clutch packs to keep the spider gears from turning, there is a hard lock that engages.


I wasn't thinking and got my words confused- in two wheel drive with the FAD disconnecting the shaft on one side... that one wheel should turn freely with nothing else internal rotating to cause noise, the other tire rotates the spider gears which could cause noise if they are damaged, and this system precludes having LSD in the front axle.
So with this set up would you say the sounds its making is abnormal or part of the lsd
 

txj2go

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So with this set up would you say the sounds its making is abnormal or part of the lsd
Nothing in there should ever make that noise. Depending on the circumstances of your test the problem could be spider gears, or could be ring and pinion, or in the case of front wheels maybe there is a problem with the FAD.
 
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