Suspension Shudder?

[MLR T1ME]

Hey all. I'm new to the group and a new HD Ram owner. I have a '21 2500 4x4 w/ 6.7 and 32k miles. After buying it I noticed a shudder in it. I took it in to the dealer and they reprogrammed the ECM per a TSB they found. That did not help. It still shuddered . I then towed my 7500lb 5th wheel camper and the shudder was amplified so I took it back. They could find nothing drivetrain related. I then took a drive with the Service Advisor and he and I agreed on the shudder we were feeling. He thinks it is suspension related, not drivetrain. I do have 285/60/R20 Nitto Ridge Grapplers on it and the dealer keeps referring to those as "oversized tires", even though they are literally .3" bigger in overall diameter than the stock 285/70R18s. Has anyone had any similar experiences with a similar situation?

 

[jsalbre]

I’m not sure what exactly you’re describing, but 285/60R20 is a stock tire size.

 

[MLR T1ME]

I’m not sure what exactly you’re describing, but 285/60R20 is a stock tire size.

Oh, believe me, I am also having THAT argument with the dealership as they keep saying I have "oversized tires". The "shudder" I am referring to is a slight shaking as you accelerate and it also occurs around 50mph.

 

[jsalbre]

Sounds like driveshaft or tire imbalance.

 

[MLR T1ME]

Sounds like driveshaft or tire imbalance.

They checked balance on tires last time, checked and removed driveshaft this time. No changes.

 

[jsalbre]

Does it feel like it’s coming from the front or rear, and is it speed dependent or the same frequency no matter your speed?

 

[MegaRed]

Torque Converter...? I've had two different rigs do it throughout the years, but nothing too recent. Hell, I don't even know if the HD's have a torque converter anymore.

 

[MLR T1ME]

Does it feel like it’s coming from the front or rear, and is it speed dependent or the same frequency no matter your speed?

Dealership says front and and now they're trying to pin it on the leveling kit that's on it and my wheel and tire combo. However, they ran it yesterday with stock wheels and tires on it from a different Ram and said you could still feel it, just not as noticeable. That tells me it's not my setup. If it's still there, it's something else. I think it's the torque converter but it's throwing no codes so they've dismissed that theory. It seems to me to be the same frequency regardless of speed. What does that tell you?

 

[MLR T1ME]

Torque Converter...? I've had two different rigs do it throughout the years, but nothing too recent. Hell, I don't even know if the HD's have a torque converter anymore.

That's the way I'm leaning but they say no because it won't throw a TC code

 

[Scram]

They should check the runout of the hubs

 

[CdnHO]

Put LS additive in the rear diff. Yes, I know it doesn't call for it. Won't kill you to try it. Worked for a buddy.

 

[JLGRacing]

That's the way I'm leaning but they say no because it won't throw a TC code

You get this figured out yet boss. I am having the same thing at about 50/55 mph

 

[johnmyster]

I took it in to the dealer and they reprogrammed the ECM per a TSB they found.

Sounds like you got 67a. Tell them you want the baseball cap and coffee mug.

That did not help. It still shuddered . I then towed my 7500lb 5th wheel camper and the shudder was amplified so I took it back.

Is it lugging in OD at/around 1000 RPM?


EDIT: Facepalm. I got necrothreaded.