8 speed clunk?

Well, all the software updates and relearnings helped a bit but my problem persisted, tje clunk was not as evident but the surging through stops and the uneven braking is what really remained unacceptable. I finally convinced my dealer to replace the transmission and torque converter. It is much better, still not perfect, but much better.

Interesting to note, the work order identifies the old tranny (core) as being Part Number UL283163AA, and the new tranny as RL283163AA.

RodRam said:

Seems like this topic has two different types of things going on well guys listen up my 2015 crew can 5.7 8 speed developed the clunk when you apply the brakes and stop then as you let off CLUNK well i figured it out and fixed it today, now all my stops are smooth as butter. These trucks have a two piece drive shaft on the rear section if you get down and look you will see a rubber accordion looking boot with two metal bands securing it this covers where the drive shaft is two pieces the rear one that slips inside the front one these two parts are fluted and slide together on the splines well i had a chevy Z71 that had a similar set up that did the same thing so it dawned on me this is exactly the same thing so today we pulled the back section of the shaft and removed the boot sure enough same concept as the chevy both pieces were supposed to be greased up good so when ypu stop the piece slides in smoothly and when you let off brake it slides back smoothly, what i found was dry spots and even some light rust ( only 10k on truck) also you could see where the the shaft was dry amd trying to slide it had made ruff marks on the wide splines, so we took some emory cloth sand paper and smoothed all the roughness ofd and greased the heck out of all the splines with Green Grease this stuff is slick as owl **** water proof and stays where you put it. Put shaft back together be sure to mark the two pieces so you get it back like it came apart then torque flange bolts to 85 lb and use 242 lock tight. I guarantee you this will fix that damn clunk! I hope the fix lasts a long time the chevy did. But if you had to redo it in 20-30k its not that hard to do took about a hour and a half but now that i now exactly what to do i could do it in a hour. Hope this helps some of you,

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This is the same clunk I've had since new. Noticeable in stop go traffic when merely letting foot of the brake pedal.

Sent from my SM-G928T using Tapatalk

UPDATE TO MY ORIGINAL FIX FOR THE CLUNK WHEN STOPPING; After about a month my clunk started too come back so on more research I pulled the driveshaft back out and removed the green grease and replaced it with C5A copper based anti seize. Its been a few months and 4k miles since and everything is still smooth as butter, no clunk at all.
Originally Posted by RodRam View Post

Seems like this topic has two different types of things going on well guys listen up my 2015 crew can 5.7 8 speed developed the clunk when you apply the brakes and stop then as you let off CLUNK well i figured it out and fixed it today, now all my stops are smooth as butter. These trucks have a two piece drive shaft on the rear section if you get down and look you will see a rubber accordion looking boot with two metal bands securing it this covers where the drive shaft is two pieces the rear one that slips inside the front one these two parts are fluted and slide together on the splines well i had a chevy Z71 that had a similar set up that did the same thing so it dawned on me this is exactly the same thing so today we pulled the back section of the shaft and removed the boot sure enough same concept as the chevy both pieces were supposed to be greased up good so when ypu stop the piece slides in smoothly and when you let off brake it slides back smoothly, what i found was dry spots and even some light rust ( only 10k on truck) also you could see where the the shaft was dry amd trying to slide it had made ruff marks on the wide splines, so we took some emory cloth sand paper and smoothed all the roughness ofd and greased the heck out of all the splines with Green Grease this stuff is slick as owl **** water proof and stays where you put it. Put shaft back together be sure to mark the two pieces so you get it back like it came apart then torque flange bolts to 85 lb and use 242 lock tight. I guarantee you this will fix that damn clunk! I hope the fix lasts a long time the chevy did. But if you had to redo it in 20-30k its not that hard to do took about a hour and a half but now that i now exactly what to do i could do it in a hour. Hope this helps some of you,

Kingcobra423 said:

I know exactly what you're talking about! When the back end of the truck settles after a full stop you feel a slight bump or clunk. It feels like slack in the transfer case or drive shaft to me.

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I have the clunk also when I start to move, like the transmission is dropping into gear after a high rev. Sometimes it also happens as I'm stopping. Called FCA and opened a case trying to resolve the issue.

OK, I'm having the same clunk problem on my 2017 Sport CC....its been there since i purchased the truck new. I now have 3500 miles on it and its still there..I'll be bringing it in for the first oil change soon and see what they say about it...

ANy update on this issue Repsol69?

Curious anyone have any stats or tally on the number of trucks affected by this?

Oddly enough this was one of the first oddities I noticed on my truck. I wasn't supper worried about it, as it is somewhat normal on the high grear transmissions but still annoying none the less. It doesn't always do it but definitely notice this on my 2014 Pentastar paired with the 8 speed. Not sure what gear ratio I have, wondering is any different for folks with a specific gear ratio?

I used to have a C300 Mercedes with the 7 speed, and did the same thing, was even worse becuase after doing it would start to vibrate while sitting at the stop. They did multiple re-flashes, clutch controler replacement and other things and never solved the problem. With shared R&D with Diamler from the days they were owned by them I'm wondering if they inheritted some of the same problems?

If you are feeling the "surge" while coming to a stop then we have to remember that these 8speed transmissions can shift gears much more aggressively than any other transmission most of us are used to.

If there's no audible clank, which may indicate ujoint issues, then the consensus is that the transmission is shifting from a higher gear straight to first gear. This is "normal" for this transmission.

If you observe the rpm while feeling the surge, you'll notice a small deflection on the needle indicating that the 8speeds inherent design is the cause for the phenomenon and is not to be worried about.

Some people have had success in reducing the surge by having the dealership reflash the shift learning program.

I have yet to do this but thought it may be helpful for someone.

Any update on this? I have a 2015 5.7 8HP70 and it does the clunk either when almost at a stop, or taking off from a stop. Once it did it while I had been stopped for a good second or two. It will do it just letting off the brake, doesn't have to be during acceleration.

I also have surging during upshifting from 1-2 and 2-3, kinda like driving a manual trans, it backs off, then slams forward.

Dealer replaced valvebody but it wasn't any better whatsoever. Have jotted down all kinds of notes and printed posts from this thread, with plans to take it back. I drove it with service manager and of course the truck wouldn't do any of this stuff while he was in the car

I used to have this issue a while back when the truck was under a year old and was led the believe that this is the transmission learning phase (or whatever it's called). It eventually went away. At around 45,000 miles my truck became very bumpy/bouncy under 5 mph. The dealer told me I needed 4 new shocks and tires, which had only 13,000 miles on them. I replaced two front tires and all shocks and it didn't help. The truck does not bounce at all when I have the car in neutral and going down a slope.

Tre said:

Any update on this? I have a 2015 5.7 8HP70 and it does the clunk either when almost at a stop, or taking off from a stop. Once it did it while I had been stopped for a good second or two. It will do it just letting off the brake, doesn't have to be during acceleration.

I also have surging during upshifting from 1-2 and 2-3, kinda like driving a manual trans, it backs off, then slams forward.

Dealer replaced valvebody but it wasn't any better whatsoever. Have jotted down all kinds of notes and printed posts from this thread, with plans to take it back. I drove it with service manager and of course the truck wouldn't do any of this stuff while he was in the car

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Disable Hill Start Assist per your user manual. Mine was through the Uconnect Settings.

This solves the issue for many people.

Just an update, I did the hill start assist disable a week and a half ago, it solved my surge problem.

Ok guys just some more general information on this thump issue on the dodge trucks, its not just the newer models its the older ones to. From my own research going through different forums years 2009-2017 have the same "thump" issue!!!

I have a 2012 dodge Ram 1500 crew cab 5.7 hemi and it has the thump issue to. I just began researching about the issue because I just bought the truck used and noticed the issue at hand.. I'm pretty concerned at this point as I'm sure others are to....Being that I'm the second owner of the truck it cancels the lifetime drivetrain warranty so I don't have that added peace of mind... I may need to get a extended warranty or something just in case... Pretty discouraged to honest....

I turned off the hill assist to see if that helps, I will keep posting updates and be involved with others on this post, we are all in this together!!!... At least I know I'm not alone on the matter, it makes me feel somewhat better...

I will begin the process of elimination and report back to you guys if I find anything that works long term, but like the tech Guy said on this forum there hasn't been any concrete fix for this issue... after reading for days of other people with the same problem I'm leaning more towards a software issue or maybe a bad drive shaft design..

Rodram reported that once He greased the slip on the drive shaft( where the double shaft connects) it fixed his temporarily, I may try this in my process of elimination... I would like to hear from rodram any updates you can give us man????

And for the tech guy would a PCM reset maybee work??? Can't a person do that them self, yea I know they say you cant, but I'm not buying that man.....Theres ppl on here saying they reset there PCM without dealership......comments will be greatly appreciated.....

Matt1984 said:

Ok guys just some more general information on this thump issue on the dodge trucks, its not just the newer models its the older ones to. From my own research going through different forums years 2009-2017 have the same "thump" issue!!!

I have a 2012 dodge Ram 1500 crew cab 5.7 hemi and it has the thump issue to. I just began researching about the issue because I just bought the truck used and noticed the issue at hand.. I'm pretty concerned at this point as I'm sure others are to....Being that I'm the second owner of the truck it cancels the lifetime drivetrain warranty so I don't have that added peace of mind... I may need to get a extended warranty or something just in case... Pretty discouraged to honest....

I turned off the hill assist to see if that helps, I will keep posting updates and be involved with others on this post, we are all in this together!!!... At least I know I'm not alone on the matter, it makes me feel somewhat better...

I will begin the process of elimination and report back to you guys if I find anything that works long term, but like the tech Guy said on this forum there hasn't been any concrete fix for this issue... after reading for days of other people with the same problem I'm leaning more towards a software issue or maybe a bad drive shaft design..

Rodram reported that once He greased the slip on the drive shaft( where the double shaft connects) it fixed his temporarily, I may try this in my process of elimination... I would like to hear from rodram any updates you can give us man????

And for the tech guy would a PCM reset maybee work??? Can't a person do that them self, yea I know they say you cant, but I'm not buying that man.....Theres ppl on here saying they reset there PCM without dealership......comments will be greatly appreciated.....

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Your truck won’t have the 8 speed, so this doesn’t really apply to you. You have the 545RFE, and if your getting a harsh 2-1 downshift then it’s not normal, where as for the 8 speed it is, for the most part.

A PCM reset may help as it will reset the adaptives.

RogerM said:

Well its not really a clunk but when coming to a stop about a second after the truck re settles its weight from braking i feel a second shift or clunk if you will almost like shifting into drive only alot softer. i feel it in the seat. Anyone else get this. Awesome forum here too. been lurking a while.

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I am having the same problems.

Tach_tech said:

Your truck won’t have the 8 speed, so this doesn’t really apply to you. You have the 545RFE, and if your getting a harsh 2-1 downshift then it’s not normal, where as for the 8 speed it is, for the most part.

A PCM reset may help as it will reset the adaptives.

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I haven't noticed that it has a rough downshift from 2nd to 1st.... I tried taking off hill start assist, didn't help..... I tightened up my spare tire, didn't help....I'm not sold on the fuel swishing back and forth causing the thump I'm below half a tank and it still thumps, others posted it only happened at 3/4 tank than stopped once around half tank..... I will fill up tomorrow and see if I notice a difference... If that doesn't help I'll do pcm reset...


I'll keep updating as I try different things.... There has to be something everyone is missing, it drives me nutts not knowing what is causing this clunk/thump........

Matt1984 said:

I haven't noticed that it has a rough downshift from 2nd to 1st.... I tried taking off hill start assist, didn't help..... I tightened up my spare tire, didn't help....I'm not sold on the fuel swishing back and forth causing the thump I'm below half a tank and it still thumps, others posted it only happened at 3/4 tank than stopped once around half tank..... I will fill up tomorrow and see if I notice a difference... If that doesn't help I'll do pcm reset...


I'll keep updating as I try different things.... There has to be something everyone is missing, it drives me nutts not knowing what is causing this clunk/thump........

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What exactly is the issue you’re experiencing?

Tach_tech said:

What exactly is the issue you’re experiencing?

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After coming to a stop I get a Light thud, like being tapped from behind... It doesn't happen all the time I'd say 20% of the time each time I drive it... I filled my tank up this morning and drove where there are a lot of stops, no thuds..... Could it really be fuel slosh???? I will keep it on full on monitor for the sake of my sanity....

Matt1984 said:

After coming to a stop I get a Light thud, like being tapped from behind... It doesn't happen all the time I'd say 20% of the time each time I drive it... I filled my tank up this morning and drove where there are a lot of stops, no thuds..... Could it really be fuel slosh???? I will keep it on full on monitor for the sake of my sanity....

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If the thud happens after you’ve already come to a complete stop, it’s not the same issue as in this thread.

If you have the larger fuel tank then chances are that’s what it is.

Will have to ask here at CTC for any issues on this,there will be a difference between fuel sloshing and a mechanical clunk.