2013 Power Wagon "Clunk" on Decel?

Hello all...

Wondering if anyone else gets this.. and if so.. is it just normal to the model, or is there an issue?

I have a 2013 Power Wagon, 5.7 6 speed auto, 30,000 miles on her... and in normal driving conditions... there is a noticeable clunk from underneath the truck many times when letting off the gas. Say, I accelerate to 50mph... I let of the gas to just cruise, the trans will shift.. and I will hear a clunk.

Thoughts? I have a long tow trip across the country in a few months, and want to make sure all is well before leaving.

I don't think a clunk is normal for any vehicle. It sounds like something loose in the drive line like u-joints, yoke, or carrier bearing if it has one. If not one of these then it could be in the trans or transfer case, or axles/rear end.

Clunk

Am guessing, being a 2013 PW, does it have the 4.56 gearing? If so, what is it's history? Off road, towing, hauling, any of these things could cause wear on the rear diff. Hope you get this diagnosed. Am interested in what you find. Running with the 4.56 gears, the ring to pinion tooth contact is about half what it would be with say a 3.73 gear. That said, wear will be greater and faster. I have installed the 4.56 on my 2014 for the towing capability. So far, so good but will know more after this summer and beyond when we start traveling. Please share your findings.

Yes, it has the 4.56 gearing... as for history, nothing too crazy. We've towed a 6000LB trailer all over michigan a few weekends a year... and to the Dakota's the first year.
Being in michigan we see a ton of snow, so a lot of 4x4 use.

I guess I will be making an appointment with the dealer!! I will report back when I find the cause!

I will say though, it sounds like someone is ringing a gong under the truck when I back down the driveway in reverse (obviously.. ) and then shift it into drive.

anyone else experience that type of clunk?

Not sure this applies but I noticed a clunk while I had about 3/4 tank of gas and it turns out the sound was the gas in the tank sloshing around...If you hear it with a full or nearly empty tank then that's not it...

I have an appointment next tues to drop her off at the dealer... I will report back.

The clunking is definitely louder when cold... and definitely on decelleration.

Well.. the dealer says they couldn't find anything. It doesnt matter that the service writer heard the loud clang when putting it into park.. and went "whoa!". So great... nothing figured out...

KarL45 said:

Running with the 4.56 gears, the ring to pinion tooth contact is about half what it would be with say a 3.73 gear.

Click to expand...

First off, I have almost 25k on my '13 PW. So, same running gear and ratios. It's been driven, towed all sorts of things, been BEATEN hard off road and seen everything from water up to it's door sills in ice water to laying on it's speed limiter for miles in triple digit temps.

(Knock on Wood) mine is smooth, tight, quiet and firm. All components (trans/transfer case/ lockers, Diffs and everything else) remain quiet and smooth in operation.

So SOMETHING is wrong with that truck. Sounds to me like you are describing old worn out pick ups when you leave the transfer case in neutral and throw the Auto Trans in Park while it is still rolling, or the internals of the Transfer Case are spinning. They clunk, bang the "Gong" and rock back and forth with all sorts of slop in the driveline and diffs as described. NOT something a new, one owner truck of this fortitude should be doing!!!

That said, I have to sort of challenge the statement that KarL45 made in the above quote. Where do you get this idea? Is the theory that the larger diameter ring gear is "thinner" than a smaller (numerically numbered "freeway" gear) would have? In all my experiences, buying and watching pros "set up" and into diffs and gear swaps, that the Pinion Gears are always fully matched to the Ring Gear (when set up and shimmed properly). And, at least they end up with the same sized "contact patch" across the board of available ratios.

Many, IMHO are thicker, with more "teeth" and thus surface in contact at any given time with one another, as the higher numerically ("lower pulling") gear sets are expected to be installed in much harsher applications, with more torque and mechanical leverage applied to it's components, from the input shaft on out.

So, fill me in if I am wrong and your info is coming from a reputable source.
I would be very surprised to find your theory to be correct.

Ed- this is very irritating to me. Take it in to another dealer for a second opinion, or to a trusted Trans or Performance shop for a look over.

I would be listening from the Flex Plate in the Auto Trans all the way back!

Something is wrong and it is ******** to get ignored like that.

Alright, just picked her up today... They had to replace a front pinion seal to fix a leak, and took another look at the noise.

All they could come up with is that nothing is wrong... and that any noise I am hearing is normal (or they could not replicate) slack in the system.

When shifting out of park to reverse on an incline... or reverse to drive on an incline, I could get them to replicate some of the noise... but they claim it is normal slack in the system so it doesn't bind.

They did say that they had made a vehicle history note, so if something comes up in the future, it was notated during the warranty period.

Dont get me wrong fellas.. I would feel a lot better if they found and fixed something... but at the end of the day, I love this truck. Maybe my paranoia is getting the better of me..

OK. Perhaps you are parking on hills and the weight of the truck is really forcing the holding cog in "Park" very firmly, and it is just the sound of it being released or engaged under pressure (it is a heavy vehicle) that is causing the "liberty bell" to ring, so to speak.


TRY THIS: Start using your Parking Brake religiously. And in doing so, apply and release it in the correct order, to ensure the vehicle is being held stationary by the brakes, rather than the mechanical bits in the transmission and driveline.

So, pull up, apply the parking brake FIRST. Then put it in Park.

When you go to leave, put your foot on the brake, holding it in place, release the parking brake, THEN pull it down into gear.

This will test to see if it is "slop" in the drivetrain, unknown pressure from parking on an undetectable grade that is really forcing the gears together, or something else. But follow the instructions above in order, to ensure the truck is being held by the brakes, and not the transmission, otherwise you will not get a clear, honest result.

*Side Tip; I hate the way the Parking Brake lever slaps back up when released. It annoys me for some reason. So, with your right foot firmly on the brake pedal, place your left foot on the Parking Brake pad and "ride it up" with the weight of you foot on it to slow and smooth it's release. It takes a little more coordination, but you might find that it smooths out your issue, eliminates a little wear and tear and hopefully will even cure your Clunk / Bang / Gong that you are experiencing.

Report back and let us know how it goes. I know it may sound silly and unnecessary, but after a few times, it will become totally routine and you will do it subconsciously as a habit and you will never think about it again.

So maybe I can help a bit. It sounds like it's just drive line slap because of the gears. Before I got my ram I had a 2001 tacoma that I regeared myself to 4.88. It started to do the exact same thing and it turned out to be the driveshaft and I just lived with it. No damage was ever done. On my new '12 1500 when I'm coasting then get on it there is a clunk caused by the slack in the system. Just something that may happen or may not (as it is for Brakelate). We have a lot of mass spinning under these trucks.