Sympathetic vibration TSB

[British Bulldog]

Just a note here for fellow 5th gen owners.
I have had a continual ‘drone’ develop in my 21 and while it was under warranty reported it.
Local dealer is brilliant and has spent hours on it. Consulted FCS TECHNICAL DEPT.
At FCA instruction replaced the amp for noise cancellation. No joy.
So there is a TSB out for this, addressing this drone at 45-50 mph. It involves a plate to stop front of truck bed below window vibrating sympathetically. They install a 1/4” plate on front of bed wall. You do see two bolts inside bed as a down side. Not judging, looking for opinions etc etc just info if you HAVE this problem. I haven’t decided yet to go ahead or not so can’t tell you if successful. They do not remove bed…….
Apparently mostly on beds with multi function tail gate? Not uncommon or unheard of.

Clive

 

[Musky Mike]

I had a drone decelerating down hill with MSD on. It was random, took to the dealer twice and they could never duplicate it. Took me a few years to figure out, but when I have some rubber made bins in the back seat, that when the drone would happens. Take them out and the drone stopped. Who would of thought some stuff in the back seat could interfere with Active Noise Cancellation system.

 

[Scottly]

If you have an old sleeping bag or large pillow, stuff it down between the bed and cap and go drive it. This should tell you if the plate will be a solution.

 

[chri5k]

I had a drone decelerating down hill with MSD on. It was random, took to the dealer twice and they could never duplicate it. Took me a few years to figure out, but when I have some rubber made tots in the back seat, that when the drone would happens. Take them out and the drone stopped. Who would have thought some stuff in the back seat could interfere with Active Noise Cancellation system.

You had children made of rubber in the back seat? That seems kind of weird.

 

[Musky Mike]

You had children made of rubber in the back seat? That seems kind of weird.

LOL....bins...totes.

 

[18harvest]

I just used a bypass harness on the noise canceling box under the seat.

 

[GTyankee]

with earlier Rams, they used vibration dampers
they stopped sounds from traveling along the frame

Mass Damper - Mopar (68051255AC)​

2013-2024 Ram - 68051255ac

​

Then FCA went to this



an article about it

RAMs Vibrate To Stay Smooth While Saving Fuel. Here’s Why - AEC

Did you know that our RAM 1500 DT models use small modules that send vibrations into their frame to make it quieter? Why you ask? To save fuel! Okay, that sounds very complicated, but it’s actually pretty clever – let’s explain. With a growing niche in the European market and the all-time...

www.aecsolutions.com

Much like noise-canceling headphones, these Active Tuned Mass Modules create a tiny vibration that counteracts those disharmonies, making the result as smooth as ever. They are fixed to various points on the truck’s frame, utilizing small electric motors that turn an unbalanced weight shaft. Their basic functionality is just the same as the vibration module in your phone.

 

[British Bulldog]

Yes. The dealer checked and cleared all those, plus the amp . That was replaced, but didn’t cure it.
This is why I am procrastinating on allowing my bed to be drilled. All this, if successful, will do is ‘mask’ the noise.
I may just do as someone suggested and stuff a quilt in REALLY tight and drive on a quiet rd!
I could also wedge a piece of plywood inside with something, again, just to try it out.
Honestly, I’ve had it checked, all drive components and critical things ok, it’s documented under warranty, turning up the radio and ignoring is beginning to work for me!

 

[British Bulldog]

I’d like to believe FCA engineers have thought this TSB through, but even the dealerships team find this an eyebrow raiser.