JL 3.6 Auto drive train noises?

[jmz68k]

Hi all

I have a 2020 Rubicon 3.6L Auto JL with d44 electronic lockers (not Limited Slip)

Since the day I got the Jeep, it has made clunking noises from the drivetrain or diff (hard to say where exactly) in stop start, slow speed traffic. It mostly happens upon deceleration when the gearbox is downshifting or if I jump on the gas too abruptly whilst moving at a slow speed.

it’s not terribly bad, but it’s noticeable. Doesn’t seem to do it as much when cold.

I will get the dealer to take a look at it, but I am unsure if this is normal or not? I would prefer them not start replacing things if they all make some driveline noises....

Thank you.

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[Sierra]

Same here. RUBICON 3.6L

 

[jmz68k]

Thanks for the reply.

As I said, it was like that from day one and has NOT become any worse with current mileage (3k)...just never driven another one to compare

Whilst it’s not a major issue, I wonder if a thicker diff oil would help given it doesn’t seem to make the noise when cold...

 

[Sierra]

Mine is like that since day 1, I ask to dealership and AS ALWAYS. ’’Its normal’’.
Every morning I turn on, press the brake, reverse, and it sounds a clunk like metal to metal.

 

[Fuel Fire Desire]

It’s not just wranglers. My 2015 Challenger did it too, and my wife’s JT. It’s lash in the driveline. As long as you don’t stand on the gas before all of the lash has been taken up (banging it into gear), it will be fine.

I’m not saying it should be there, but from my experience with FCA products since the new 8 speed transmissions came out, it seems to be normal.

I don’t know for a fact, but I believe the lash is cumulative slop from the transmission output, driveshaft, and rear end. When torque is applied in either direction, everything clunks together.

Once in gear, I don’t notice it in the JL or JT. But it was there all the time in the Challenger, since in sport mode (which I left on most of the time) it aggressively downshifts under braking to improve braking performance. There was a constant abrupt reversal of torque input to the driveline. Though, after 3 years of ownership and spirited driving, it never got any worse.

 

[jmz68k]

Thanks Fuel Fire Desire
Is your JL/JT a Rubicon? Wonder if it’s just the Rubicon’s with the extra lash..

 

[Fuel Fire Desire]

Thanks Fuel Fire Desire
Is your JL/JT a Rubicon? Wonder if it’s just the Rubicon’s with the extra lash..

The JLU is a Sport S, the JT is a hard base model Sport.

 

[YYC_Rubicon]

My 2020 Rubicon makes the same noise and has since day 1. I’ve chalked it up as normal at this point at 26k Km’s.

 

[jmz68k]

Thanks for the feedback all....not sure I will bother bringing it up with the dealer now...I feel like it would create more problems by pulling things apart to investigate something that is ‘normal’

 

[iamstillvince]

mine is a 2020 3.6 sport auto but it's silent, i came from a 9spd auto on my renegade, the 9 sp was a disaster of a transmission so maybe im just so happy with this im not noticing ?

 

[Fuel Fire Desire]

Thanks for the feedback all....not sure I will bother bringing it up with the dealer now...I feel like it would create more problems by pulling things apart to investigate something that is ‘normal’

I brought the Challenger up with the dealer. They didn’t even want to see it. They immediately said it was compounding lash stemming from the two piece drive shaft and said it was normal, but if it got worse to bring it in. It never got worse.

 

[Xcoaste]

My '21 JLUR 3.6 auto makes a similar noise, but I only started hearing it now that I have my windows down. Only notice when first engaging out of my garage. To me it sounds like a spring hitting metal, and I almost want to say I can feel it around the centerline of the Jeep (tranny). Drives great though!

 

[jy86206]

2.0 Sport Altitude. The 3-2-1 downshift is somehow rough, especially when the tranny is cold, I can hear the clunk from drive line while it downshifts 3-2 and sometimes jerks. It doesn't always happen, typically happens when I stop the car slowly, like coasting with half way pedal, it suddenly kick from 3rd to 2nd, incline makes it worse. 2-1 is ok for me, in 2.0 it seems to downshift earlier so that I don't have the harsh 2-1 like in my old 3.6 WK2. I know that the FCA manufactured transmission is not perfect so I don't have much expectation on it, just the clunk sound makes me a little nervous, I think part of the reason is that we hear more things in a JL. Another thing is that I can hear one click sound from rear end when the car is about to stop, if it starts rolling right after stop, I hear another click, this sounds like something has play in the driveline.

 

[Headbarcode]

I get the same clunk going into drive, but only when it's cold from sitting all night. It'll happen if parked on even the slightest incline, and the Jeep is allowed to lean on the park dog. I made the habit, a couple of days into ownership, to set the ebrake while in neutral, ease up on the brake pedal to let the jeep settle, and then put it in park. On the next cold start, foot on the brake, put it in drive without a clunk, release the ebrake, and away I go. Works every time.

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