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Discussion Starter #1
I’m new to the Jeep world so bare with me. I have a 2018 Limited with 42k km on it. When the weather drops to -5c I feel a slight vibration from the rear but only when turning. The vibration goes away after driving a little bit but my commute only has around 4 turns so I don’t know when it disappears.

Is this normal? Cold diff oil? Underlying problem?
 

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Are you feeling the vibration in the seat or steering wheel? How do you know it is from the rear? I ask because I have a similar vibration (felt in the lumbar area of the driver's seat) when the vehicle is started cold and I make the first few turns from my neighborhood. I reported it to the dealer who said it is from the exhaust system. What I have noticed is that it nearly goes away once the vehicle is up to operating temperature.
 

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I have had vibrations from one end of the car that felt like it was from another end of the car..... ....it can be deceiving so do not assume its the Rear, just because it feels/sounds like its coming from the rear....

It would help if you told us what engine/trans/4WD system you have.....
If you have QDII with the rear ELSD, cold and more viscous fluid could very well cause vibrations from the clutch discs not slipping as smoothly as they should....
If you have all open differentials, that is all the other 4WD/2WD systems, I have a tough time believing cold fluid is causing a vibration in turns, but I suppose its possible....

Its just as likely the brakes or driveshaft joints reacting to the cold....

Tires are another one... ....are they at least the recommended pressure and even pressure left/right? A very cold tire low on pressure, or more than 1-2 psi difference left/right, I could see cause some NVH while driving till they warm up....

The WK2 has the Drum-in-Hat parking brake, that has been troublesome in the past.....
The Brake Light is triggered by a switch in Parking Brake Pedal mechanism, so it only goes on when the pedal is pressed..... ....but my experience with Drum-in-Hat parking brakes in other vehicles is they need slack or lash in the parking brake (which the Manuals all say to adjust them with that extra Lash in them) or they will uncommanded catch and engage with expansion/contraction with temperature changes.... ...then the kicker is, if you adjust them with too much lash, they won't engage enough to hold the vehicle on a hill....
Again, its only one of several possibilities... ....a good test might be engage your parking when the vehicle is cold soaked in that weather and see how it reacts.... ...a properly adjusted parking brake, the pedal will be a light force at first progressively increasing to a moderate force by the time you hit the very limit of the pedal push.... ....too tight (i.e. not enough lash) it will start moderate and become extreme and/or you won't be able to get it to the pedal limit... ...too loose (i..e too much lash) will be very little force and only light when you've hit the limit of the pedal...

...too loose shouldn't create a problem while driving (although its possible for the shoes to freeze in place pressed up against the drum and that would create a loose pedal, although the parking brake is engaged)... ...the brake won't hold the vehicle on a hill though...
...too tight can create problems....

...My parking failed during summer, the mechanism seized with the parking brake engaged on one brake and it was making an awful squeal when cold, but unnoticeable once warmed up....
 

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If you have QDII with the rear ELSD, cold and more viscous fluid could very well cause vibrations from the clutch discs not slipping as smoothly as they should....
If you have all open differentials, that is all the other 4WD/2WD systems, I have a tough time believing cold fluid is causing a vibration in turns, but I suppose its possible....
I am not trying to hijack this thread, but this is the conclusion I was starting to come to with the vibration I feel. I have felt it in other GCs as well -- each of those had the QDII system as well. I accept it as a characteristic of the vehicle and not an issue with mine in particular. I wish it weren't present, but I accept and understand it.
 

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Discussion Starter #5
I have had vibrations from one end of the car that felt like it was from another end of the car..... ....it can be deceiving so do not assume its the Rear, just because it feels/sounds like its coming from the rear....

It would help if you told us what engine/trans/4WD system you have.....
If you have QDII with the rear ELSD, cold and more viscous fluid could very well cause vibrations from the clutch discs not slipping as smoothly as they should....
If you have all open differentials, that is all the other 4WD/2WD systems, I have a tough time believing cold fluid is causing a vibration in turns, but I suppose its possible....

Its just as likely the brakes or driveshaft joints reacting to the cold....

Tires are another one... ....are they at least the recommended pressure and even pressure left/right? A very cold tire low on pressure, or more than 1-2 psi difference left/right, I could see cause some NVH while driving till they warm up....

The WK2 has the Drum-in-Hat parking brake, that has been troublesome in the past.....
The Brake Light is triggered by a switch in Parking Brake Pedal mechanism, so it only goes on when the pedal is pressed..... ....but my experience with Drum-in-Hat parking brakes in other vehicles is they need slack or lash in the parking brake (which the Manuals all say to adjust them with that extra Lash in them) or they will uncommanded catch and engage with expansion/contraction with temperature changes.... ...then the kicker is, if you adjust them with too much lash, they won't engage enough to hold the vehicle on a hill....
Again, its only one of several possibilities... ....a good test might be engage your parking when the vehicle is cold soaked in that weather and see how it reacts.... ...a properly adjusted parking brake, the pedal will be a light force at first progressively increasing to a moderate force by the time you hit the very limit of the pedal push.... ....too tight (i.e. not enough lash) it will start moderate and become extreme and/or you won't be able to get it to the pedal limit... ...too loose (i..e too much lash) will be very little force and only light when you've hit the limit of the pedal...

...too loose shouldn't create a problem while driving (although its possible for the shoes to freeze in place pressed up against the drum and that would create a loose pedal, although the parking brake is engaged)... ...the brake won't hold the vehicle on a hill though...
...too tight can create problems....

...My parking failed during summer, the mechanism seized with the parking brake engaged on one brake and it was making an awful squeal when cold, but unnoticeable once warmed up....
Sorry! 3.6L QT2 I don’t know if that comes with ELSD. I feel it in my seat not the steering and it just feels like a rumble from the back. I guess I can’t confirm it’s the back or not.
 

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Sorry! 3.6L QT2 I don’t know if that comes with ELSD. I feel it in my seat not the steering and it just feels like a rumble from the back. I guess I can’t confirm it’s the back or not.
This sounds exactly like what I experience as well. I think it's a normal characteristic of the vehicle when cold.
 

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I am not trying to hijack this thread, but this is the conclusion I was starting to come to with the vibration I feel. I have felt it in other GCs as well -- each of those had the QDII system as well. I accept it as a characteristic of the vehicle and not an issue with mine in particular. I wish it weren't present, but I accept and understand it.
I've seen multiple posts from WK/XK through WK2, that noise, vibration and binding from the ELSD's is cured with fresh fluid that has the correct amount of friction modifier in it. Its not hard to imagine the fluid degrades with time and use, and doesn't let the clutch pack slip as smoothly as it should.

Those complaining of some harsh wind-up accellerating from a stop, with QTII and QDII, also found fresh XFR Case fluid solved it. The WK2 QTII and QDII has a clutch pack in it, degraded fluid will make the clutch pack engage more harshly.
Sorry! 3.6L QT2 I don’t know if that comes with ELSD. I feel it in my seat not the steering and it just feels like a rumble from the back. I guess I can’t confirm it’s the back or not.
You do NOT have an ELSD, only QDII has an ELSD, and QDII is just QTII with a rear ELSD added to it.
This sounds exactly like what I experience as well. I think it's a normal characteristic of the vehicle when cold.
He should still check his tire pressure, in Winter the tires get colder and the air pressure in them goes down...
Most WK2's have a recommended tire pressure of 36PSI, check the decal on the driver's side door jamb, it can go down to 30PSI before the TPMS lights a warning lamp.... ....but tires 6 PSI low on pressure, cold soaked in -5°C weather, I could see vibrating until they warm-up a bit and tire pressure goes up....

And 36PSI is the cold pressure, i.e. check and service when the tires are cold soaked, not hot just after driving.... ...if you have to go the gas station, then wait till the tires are cold soaked and drive directly and slowly to the gas station, within 3 miles to add air to the tires...
 

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I've seen multiple posts from WK/XK through WK2, that noise, vibration and binding from the ELSD's is cured with fresh fluid that has the correct amount of friction modifier in it. Its not hard to imagine the fluid degrades with time and use, and doesn't let the clutch pack slip as smoothly as it should.

Those complaining of some harsh wind-up accellerating from a stop, with QTII and QDII, also found fresh XFR Case fluid solved it. The WK2 QTII and QDII has a clutch pack in it, degraded fluid will make the clutch pack engage more harshly.
Mine is a 2019 Trailhawk with 6k miles that was built in June of 2019. I don't think the fluid would be bad in this short a period of time...unless the fluid was never right from the factory.

Also, you talk about the transfer case (XFR), but we're talking about the rear differential fluid...or so I thought. Which are you referring to?
 

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Discussion Starter #9
I've seen multiple posts from WK/XK through WK2, that noise, vibration and binding from the ELSD's is cured with fresh fluid that has the correct amount of friction modifier in it. Its not hard to imagine the fluid degrades with time and use, and doesn't let the clutch pack slip as smoothly as it should.

Those complaining of some harsh wind-up accellerating from a stop, with QTII and QDII, also found fresh XFR Case fluid solved it. The WK2 QTII and QDII has a clutch pack in it, degraded fluid will make the clutch pack engage more harshly.

You do NOT have an ELSD, only QDII has an ELSD, and QDII is just QTII with a rear ELSD added to it.

He should still check his tire pressure, in Winter the tires get colder and the air pressure in them goes down...
Most WK2's have a recommended tire pressure of 36PSI, check the decal on the driver's side door jamb, it can go down to 30PSI before the TPMS lights a warning lamp.... ....but tires 6 PSI low on pressure, cold soaked in -5°C weather, I could see vibrating until they warm-up a bit and tire pressure goes up....

And 36PSI is the cold pressure, i.e. check and service when the tires are cold soaked, not hot just after driving.... ...if you have to go the gas station, then wait till the tires are cold soaked and drive directly and slowly to the gas station, within 3 miles to add air to the tires...
Last I checked they were at 33 psi cold. I didn’t think 3 psi would make such a huge difference. I didn’t want to add more air because they would be over 36 when hot?
 

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Last I checked they were at 33 psi cold. I didn’t think 3 psi would make such a huge difference. I didn’t want to add more air because they would be over 36 when hot?
Its possible, a very cold tire under pressure could cause some vibration until it warms up and becomes more flexible....

The recommended tire pressure on the Driver's Side Door Jamb Decal, is the "Cold" pressure, it is 100% normal and designed for the pressure to go higher than the cold pressure as the tires warms up....
The tire will go to hundreds of PSI before it bursts....
The recommended pressures have to do with heat, load and the cross-section shape of the tire and tread.....

The recommended pressure on the door jamb is the lowest pressure you should have in the tires, you can go higher if you want, but no higher than the max pressure molded into the sidewall of the tire....

Pressure too low or high, will change the shape of the tire cross-section and how squarely the tread rolls on the road, that is why the wrong tire pressure causes uneven tread wear....

Pressure too low also causes the sidewall to bulge and thus bend and flex and build up heat which could compromise the tire....

Pressure to high will cause the less surface of the tread to contact the road and have negative handling qualities....

I've set tires cold at 44PSI, max pressure, and while driving and getting them hot, I've seen 48PSI, everything was fine, tear wear, handling, nothing went wrong with the tire....

I've had 36PSI in my tires of late, and typically see 39 or 40 PSI at highway speeds, its just fine, the manufacturer's of both the vehicle and tires will tell you the recommended tire pressure is the "cold" tire pressure. It 100% acceptable the tire pressure goes higher as the tires get warmer as you drive.

I'd up your tire pressure to 36PSI and see if that makes a difference?
 

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Discussion Starter #11
Its possible, a very cold tire under pressure could cause some vibration until it warms up and becomes more flexible....

The recommended tire pressure on the Driver's Side Door Jamb Decal, is the "Cold" pressure, it is 100% normal and designed for the pressure to go higher than the cold pressure as the tires warms up....
The tire will go to hundreds of PSI before it bursts....
The recommended pressures have to do with heat, load and the cross-section shape of the tire and tread.....

The recommended pressure on the door jamb is the lowest pressure you should have in the tires, you can go higher if you want, but no higher than the max pressure molded into the sidewall of the tire....

Pressure too low or high, will change the shape of the tire cross-section and how squarely the tread rolls on the road, that is why the wrong tire pressure causes uneven tread wear....

Pressure too low also causes the sidewall to bulge and thus bend and flex and build up heat which could compromise the tire....

Pressure to high will cause the less surface of the tread to contact the road and have negative handling qualities....

I've set tires cold at 44PSI, max pressure, and while driving and getting them hot, I've seen 48PSI, everything was fine, tear wear, handling, nothing went wrong with the tire....

I've had 36PSI in my tires of late, and typically see 39 or 40 PSI at highway speeds, its just fine, the manufacturer's of both the vehicle and tires will tell you the recommended tire pressure is the "cold" tire pressure. It 100% acceptable the tire pressure goes higher as the tires get warmer as you drive.

I'd up your tire pressure to 36PSI and see if that makes a difference?
I’ll give that a shot.
Thank you and everyone else for all the information. I’m always willing to learn. The GC is slightly different from the Honda’s I’ve had.
 

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I’ll give that a shot.
Thank you and everyone else for all the information. I’m always willing to learn. The GC is slightly different from the Honda’s I’ve had.
Please let us know if that helps out or not. I run 265/65/18" Michelin Defenders on my 2019 Trailhawk. While not an all-terrain tire, they ride a world smoother. That also had something to do with upping the sidewall ratio from 60% to 65%. In any case, I run them at 33PSI cold, which is the placard pressure for 265/60s, and have been watching the tread shoulders to ensure they are getting full contact. So far, so good.
 

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I’m new to the Jeep world so bare with me. I have a 2018 Limited with 42k km on it. When the weather drops to -5c I feel a slight vibration from the rear but only when turning. The vibration goes away after driving a little bit but my commute only has around 4 turns so I don’t know when it disappears.

Is this normal? Cold diff oil? Underlying problem?
Hello TCBK,
We are sorry to hear about your most recent concern. Unfortunately due to the nature of our team we are unable to assist customers outside of the United States. However, if you are interested in additional assistance I have provided a customer care # for potential help:
1-877-426-5337
Laura
JeepCares
 
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