Constant Clunk

[JS4024]

So I have a 2017 6.4, 16,000 miles. Have taken it to dealer for a clunking noise in the drive line. Always happens at about 1500 rpms, let off gas coast, go back on gas and CLUNK. Also happens when slowing to make a slight left turn, go back on gas CLUNK. Sometimes happens when coming to a stop CLUNK. Has been to the dealer 8 times and they say it is “normal”. Tech specialist in the area said it’s “normal”. They will do nothing further to attempt to investigate or fix it. 3 friends have the EXACT same build off the build sheet.... you guessed it, no CLUNK. If my truck is “normal” theirs must be abnormal. At wits end.... any ideas or folks with similar issues? They did shim the pinion bearing. That’s all they tried. Thanks!!

Additional:: They also at my request put the TC back to learn mode because it does seem to “hang” while down shifting almost like it’s in tow haul. It happens always right around 1500 rpms and I would have to say 3rd or 4th gear. I have to say the clunk comes from the rear end but it’s hard to isolate. If I am above say 1800 rpm never get a clunk. Only letting off gas going back on. Occasionally when braking and letting off. The dealer service writers now blow me off completely even though they “know” it clunks. I can make it clunk at will on demand. I even asked them to plug in the diag tool while I drove it too watch the TC to see if the torque converter clutch was sticking and they said “no”, our district tech said it drives normally. Love the truck, hate the clunk and the give 2 $hits attitude from the service department!

 

[mtofell]

In my experience and many others here, if your truck moves and isn't on fire the dealer says it's "normal" so that part is not too surprising. I've seen a few posts like this go around and most people suggest U-joints. There are also a variety of front end suspension parts that could cause what you describe. My tranny also clunks sometimes in situations like you describe so you might set the EVIC to where you can see what gear you're in and note if the clunks are related to gear changes at all.

 

[bigdodge]

These trans r noisy for most. Mine was similar to yours. Almost like it hangs up on down shifting. I decided to change my trans fluid with redline and has stopped ever since. Can't say it will work for everyone or even the technical aspects of why it did for me but it's been over a year and it's not done it since.

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[Elevated 2013]

Is the noise coming from the front or back of the truck? Is your spare tire as high up as it can go? Have you checked your engine and trans mounts? These are just some common things that clunk when you accelerate or slow down that I’ve seen outside of the u joints in the driveshafts.


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[2003F350]

My '17 PW also does this from time to time. It did it a LOT more when it was newer - I'm pushing 34,000 miles now and the clunks have all but gone away - in fact I can't remember the last time it actually did it. But you described what mine was doing precisely.

 

[mtofell]

I once left a couple bottles in one of the bins under the rear floor mats and that had me scratching my head for a couple days until I remembered. Definitely a long shot but have you checked the bins?

 

[HammerHead]

My 2018 6.4 does the same thing, The only thing that helps this is by putting the truck in manual mode and leaving it in fourth gear while I’m in town. And sometimes third gear if there’s traffic.

 

[Ribtipram]

I have herd my 16 long bed 6.4 do it before too. Only a couple of times. Slow speed on and off the gas. Ive tried to get it to do it when i want it to but it seems to do it when it wants. I have been trying to watch if mds is on and what gear shes in when it happens. It just dont happen enough to track it down