Shudder/shake from rear end at very slow speeds, typically while turning.

[TWRam]

Sometimes when I apply the gas lightly, I will feel a significant shudder/shake from the rear end from about 0-3 MPH or so. I can duplicate it when the truck has been recently started, in drive, 1 foot on the brake, and one foot barely on the gas, and modulating the brake to maintain 1-2 MPH while turning. It is a constant shake from the rear end or a shudder. It shakes the whole truck.....not violently, but notably....like running over some rumble strips in the road at lower speeds. Frequency is too fast to be U-Joints. When trying to duplicate it using the method above, it goes away when the wheel is straight, but progressively worse with decreasing radius while turning. Doing some digging, I learned that our anti-spin rear end is a clutch type. One theory of mine that seems to explain the symptoms would be that the clutches in the LSD rear end are chattering. (Cold clutches and fluid, tight radius turning, torque applied to rear end, making the clutches grip tighter and chatter against each other). I have also noticed that it is more pronounced when going uphill (more torque on the LSD clutches causing increased chatter) The only evidence against this is that I swear I have experienced it in a straight line once before. I do know that it happens primarily while turning, like when making a right hand turn from a stop at an intersection. Has anyone else experienced this?

When regular (non LSD) diff fluid is used in a clutch type LSD application, it will cause chatter around turns. Knowing this, I'm tempted to swap the diff fluid out with some synthetic with LSD modifier just to double check that it has the right fluid!

 

[DAWNHAMMER]

I haven’t experienced that. But my truck jerks and lurches around likes it’s going to stall out when I’m between 1-3 mph with light breaking. It pisses my wife off constantly. Just about any time I come to a red light it happens.

I just assumed it had something to do with the 3.92 gearing.


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[MQQSE]

Sometimes when I apply the gas lightly, I will feel a significant shudder/shake from the rear end from about 0-3 MPH or so. I can duplicate it when the truck has been recently started, in drive, 1 foot on the brake, and one foot barely on the gas, and modulating the brake to maintain 1-2 MPH while turning. It is a constant shake from the rear end or a shudder. It shakes the whole truck.....not violently, but notably....like running over some rumble strips in the road at lower speeds. Frequency is too fast to be U-Joints. When trying to duplicate it using the method above, it goes away when the wheel is straight, but progressively worse with decreasing radius while turning. Doing some digging, I learned that our anti-spin rear end is a clutch type. One theory of mine that seems to explain the symptoms would be that the clutches in the LSD rear end are chattering. (Cold clutches and fluid, tight radius turning, torque applied to rear end, making the clutches grip tighter and chatter against each other). I have also noticed that it is more pronounced when going uphill (more torque on the LSD clutches causing increased chatter) The only evidence against this is that I swear I have experienced it in a straight line once before. I do know that it happens primarily while turning, like when making a right hand turn from a stop at an intersection. Has anyone else experienced this?

When regular (non LSD) diff fluid is used in a clutch type LSD application, it will cause chatter around turns. Knowing this, I'm tempted to swap the diff fluid out with some synthetic with LSD modifier just to double check that it has the right fluid!

When I read your post I thought I wrote it... What you describe is exactly what my truck is doing, down to every word.

At first I thought maybe it was one of the clutches in the transmission, but like you said, when you straighten the steering wheel it goes away. I was going to take it to the dealer but I wanted to check it out further as I absolutely hate dealer techs trying to diagnose things and crawling all over my perfect truck.

I took my truck to a quiet parking lot and noticed I could easily duplicate the issue, and I could make it worse by placing the truck in reverse and ****ing the wheel all the way to one or the other direction and giving it gas. After doing all types of moves I found that it is either the axle clutches or the anti locking safety system. I'm almost positive it's the anti locking safety system over acting because it thinks its about to engage. Another thing I tried was, when the truck was doing it's chattering I switched the transmission in natural and the chattering stops (even with the wheels turned). I can also feel the chattering in the steering wheel so the electronic steering has my attention as a possible culprit as well.

The truck is smooth as butter going down the road, the steering is perfectly straight and no squeaks or issues whatsoever. I've owned a lot of trucks,(new) and I mean a lot. This truck is the smoothest most silky straight truck I've ever owned and there is nothing that compares. I've also owned cars over $100K that did not drive as smooth as this truck so I'm tempted to leave this issue alone until I find someone else like you (or others) that will identify the issue and find the proper adjustment. The all around truck performance is outstanding and I don't want to mess with something and end up screwing up the perfect smoothness. Please do let me know if you find something...
Anyway, yup, same on my truck...

 

[RamCares]

Hi Everyone,

We are sorry to hear that you all have concerns with your new Ram trucks. We understand how frustrating it must be. If any of you decide to visit the dealer for these concerns, please send our team a private message so that we can provide additional support.

Darlene
Ram Social Care Specialist

 

[MG99]

Any updates on this shudder issue?

Mine only vibrates when I lightly press the brake and let it roll very slowly (1-2mph). Haven’t tried while turning. Feels like brake pads or rotors to me, but I don’t feel any vibration when coming to a complete stop.

 

[pilottim]

My '19 Longhorn 4x4 with 3.92 LSD rear end just started doing this too at 12k miles. As noted, it is worse when turning one direction then backing up in the other direction. The rear diff grinds and starts clicking as I straighten out. I have a list of things for the dealer to look into at the next appointment. I'll bring this up and report after my next dealer visit.

 

[RamCares]

My '19 Longhorn 4x4 with 3.92 LSD rear end just started doing this too at 12k miles. As noted, it is worse when turning one direction then backing up in the other direction. The rear diff grinds and starts clicking as I straighten out. I have a list of things for the dealer to look into at the next appointment. I'll bring this up and report after my next dealer visit.

I apologize for the trouble, @pilottim. Please know that our team is just a private message away and we are more than happy to get you set up with a specialist for further support as you address this with your dealer.

Mark
RamCares

 

[Billy James]

Following....I have the same thing.

 

[Grimson]

Just got the same at only 9,000 miles with my 3.92 diff. Pulled my TT (9990 GVCW) several times this summer and it became noticeable unhitched a few days ago. Drained diff fluid, filled with Mobil 1 75w140 and ~2oz LS Friction Modifier and it’s gone...but for how long?


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[Scram1500]

Almost sounds like loose or broken trailing arm bushings

 

[blakei]

Hi all, I’m having the same issue! Also could have written the first post - same symptoms. I have a 2020 Big Horn with the 3.92 anti-slip rear end.

This showed up around 3500 miles and the truck now has 5100 miles. We are towing an 8000 lb travel trailer.

The only thing I can add to the convo is it seems worse in hot weather. A few weeks ago when towing in 100+ heat it was quite noticeable. When back at home in mid-70s it seemed to mostly go away. Yesterday it was 106 and quite loud.

It almost sounds like brakes not fully releasing. Is that part of the anti slip system? Has anybody found any resolution? After another camping trip this week I’m going to the dealer.

I have a video of the issue — now added via YouTube

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[RJNavarrete]

Following because I think I have this.

 

[bpulli]

Anyone with this issue have success with the dealer diagnoses and resolution? I have the same issue

2020 Bighorn 4x4 3.92 axle, 4100 miles and exact same problem. Truck was fine until this weekend, I returned from a trip where I towed my 6000lb travel trailer about 700 miles round trip. I dropped the trailer off and noticed the shutter / grinding sound from the rear end when turning. I took the truck to an open parking lot and was able to replicate the problem in forward and reverse each time I turned the wheel and accelerated from a stop.
I am super turned off with Ram right now as I bought this truck due to the high tow capacity for a 1/2 ton and after the 1st time towing my 50k 2020 truck sounds like a 1990 POS!

 

[blakei]

I have an a service appointment first week of October. Hope to learn more then. My research seems to confirm the OP - it’s limited slip differential clutch chatter. Different gear oil and additive might help - if the dealer plays dumb I may swap it myself.

Most of us with this issue seem to be towing (relatively) heavy loads. I noticed it’s worse in hot weather, so makes me think could be lube related (stock gear oil can’t handle high heat/stress?).


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[nburd]

I have noticed this as well from 500-2500 miles. Lately not so much. I do not know if its better or I do not sense it anymore. It must be a very common issue, if it's an issue at all. I have the electronic diff so I do not think it Diff related. It does feel like an ABS or traction issue. I will try see if it's still active.

 

[RamCares]

Anyone with this issue have success with the dealer diagnoses and resolution? I have the same issue
2020 Bighorn 4x4 3.92 axle, 4100 miles and exact same problem. Truck was fine until this weekend, I returned from a trip where I towed my 6000lb travel trailer about 700 miles round trip. I dropped the trailer off and noticed the shutter / grinding sound from the rear end when turning. I took the truck to an open parking lot and was able to replicate the problem in forward and reverse each time I turned the wheel and accelerated from a stop.
I am super turned off with Ram right now as I bought this truck due to the high tow capacity for a 1/2 ton and after the 1st time towing my 50k 2020 truck sounds like a 1990 POS!

I have an a service appointment first week of October. Hope to learn more then. My research seems to confirm the OP - it’s limited slip differential clutch chatter. Different gear oil and additive might help - if the dealer plays dumb I may swap it myself.
Most of us with this issue seem to be towing (relatively) heavy loads. I noticed it’s worse in hot weather, so makes me think could be lube related (stock gear oil can’t handle high heat/stress?).

I have noticed this as well from 500-2500 miles. Lately not so much. I do not know if its better or I do not sense it anymore. It must be a very common issue, if it's an issue at all. I have the electronic diff so I do not think it Diff related. It does feel like an ABS or traction issue. I will try see if it's still active.

Hi all,

I apologize for the frustration on this concern. We would be more than willing to ensure that your experiences are formally documented and that you have the additional support of a customer care specialist who can work alongside both you and your dealer while in service.

We are always a private message away.

Mark
RamCares

 

[blakei]

Update on this issue. Got into the dealer last week and showed them the videos I had recorded. They acknowledged it was not a normal nor healthy sound. After some road testing, they told me they couldn't replicate it...not a surprise. I asked them to road test again on some small nearby hills and turn from a stop uphill. They did, and they were able to replicate the issue.

To resolve the issue, they added "one bottle of friction modifier" which is part 4318060-AD. The bottle appears to be 4 oz. This seems to have resolved the issue in my limited testing so far! Usually when I pulled out of driveways or reversed with a tight turn I'd get the shudder / slip. None so far; I'll do some more driving in the coming weeks (including hills) and will update if it's gone away.

I'm impressed the dealer actually tried multiple times to find the issue, and they took care of it under warranty - $0 to me.

I wouldn't be surprised if the shudder/slip does not return...the LSD may actually slip too much now and may act as more of an open differential because the owners manual indicates
"1500 Model rear axles equipped with a Limited Slip Differential require that 5 oz. (148 ml) MOPAR Limited Slip Additive be added to the gear lubricant." If it already had 5 oz in it and they added another 4 oz... that's a lot of friction modifier. Who knows how it was actually filled at the factory although I'd hope it was to spec.

Did anyone else add friction modifier, and did this resolve your issue?

 

[Billy James]

Update on this issue. Got into the dealer last week and showed them the videos I had recorded. They acknowledged it was not a normal nor healthy sound. After some road testing, they told me they couldn't replicate it...not a surprise. I asked them to road test again on some small nearby hills and turn from a stop uphill. They did, and they were able to replicate the issue.

To resolve the issue, they added "one bottle of friction modifier" which is part 4318060-AD. The bottle appears to be 4 oz. This seems to have resolved the issue in my limited testing so far! Usually when I pulled out of driveways or reversed with a tight turn I'd get the shudder / slip. None so far; I'll do some more driving in the coming weeks (including hills) and will update if it's gone away.

I'm impressed the dealer actually tried multiple times to find the issue, and they took care of it under warranty - $0 to me.

I wouldn't be surprised if the shudder/slip does not return...the LSD may actually slip too much now and may act as more of an open differential because the owners manual indicates
"1500 Model rear axles equipped with a Limited Slip Differential require that 5 oz. (148 ml) MOPAR Limited Slip Additive be added to the gear lubricant." If it already had 5 oz in it and they added another 4 oz... that's a lot of friction modifier. Who knows how it was actually filled at the factory although I'd hope it was to spec.

Did anyone else add friction modifier, and did this resolve your issue?

I'll let you know in a few days. I just ordered some friction modifier. I'm planning on draining my axle and refilling though.

 

[blakei]

I'm planning on draining my axle and refilling though.

Any luck with the drain and refill? If so, how much modifier did you use?


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[Billy James]

Any luck with the drain and refill? If so, how much modifier did you use?


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I actually have it at the shop today for them to look at it. If they don't come up with anything; then I'll start experimenting.