Deep rumbling when truck loaded (with cargo or TT)

[trailernovice]

At certain speeds, and only when the truck (in signature) is heavy with either people, cargo, or the TT (tongue weight per Jayco is 470 dry), the truck has an 'almost-too-low-and-too-deep-to hear' rumble that lasts until the truck gets either above or below the 'problem' speed....it happens at around 10mph and again at around 35 mph..

It's clearly body and/or suspension...definitely not mechanical

The truck has never been wrecked (bought it new off the lot, so I'm sure of this), so it's not a flawed repair job that left something unbalanced or misaligned and thus vibrating

It just started doing this in the past several months

I'm thinking it could be the failure of some sort of bushing or something else that isolates the body from the suspension...

I'd appreciate any thoughts

[Grit_dog]

trailernovice wrote:
new driveshaft installed...went on a run of about 200 miles over Labor Day weekend....no rumbling at all...hopefully we have found and resolved the issue

Good to hear.
But I didn’t know that any of the new 1500s had 2 piece driveshafts. Maybe they do in the longest rear shaft configurations offered?
If it’s a 1 piece though, it virtually impossible it was the type of “driveline shudder” that was mentioned and also described by you. Because that can’t really happen with a solid driveshaft, no carrier bearing.

[BobsYourUncle]

Awesome, great to hear!

[trailernovice]

new driveshaft installed...went on a run of about 200 miles over Labor Day weekend....no rumbling at all...hopefully we have found and resolved the issue

[BobsYourUncle]

It's really great when the OP reports back with the solution, or apparent solution. Thanks for that.

Most never bother, making all of us wonder if something ever got resolved. If this has resolved your issue, it strengthens those who pointed you at a driveshaft / driveline issue. It shows who was good at diagnosing it, and helps for similar future situations. And, now you can speak from experience too.
Kudos to Jimlin

Do let us know how it is after a few runs under the same circumstances.
:):)

[trailernovice]

To Jimlin and others who tagged it as a driveline issue...thx...you seem to have hit the nail on the head

After much back and forth between dealership, regional tech rep, and factory support, the solution which will hopefully resovle the issue--replacement of the driveshaft--has been done

[JIMNLIN]

Service writer can't be certain, especially sight unseen....but said something like, "years ago, in the previous series of 1500's, we had this issue...traced it back to the drive shaft being shifted to a weird angle when the vehicle is heavily loaded"...apparently their (then) solution was some sort of lifting block, that solved the problem when under load but created the situaation of rumbling when the trucks would be empty

Its called drive line shudder.
When Dodge came out with the new 3rd gen 2500/3500 trucks in '03 they had a SB to cover that issue with the two piece drive shaft.
My '03 (in sig) had the shudder under hard acceleration under 15 mph with a heavy load.
The new 3rd gen had no upper over load spring pack and was a weak sister with just 1800 lbs in the bed.
I fixed my drive line shudder issues before the SB came out by adding Supersprings to the rear suspension.
The SB changed the drive line angle with a different center carrier bearing mount.

[stickdog]

I'd go with the driveshaft. Had the same problem with a 3/4 Chevyvan had something to do with a twist in the axle and the driveshaft rear Ujoint while loaded and under torque.

[BobsYourUncle]

I agree with Tyler.
My first thought was U-joint or wheel bearing.

[trailernovice]

Tyler:
You know your stuff! After I posted, I realized, "wait! this thing's under extended warranty! I can just call the dealer"...

Service writer can't be certain, especially sight unseen....but said something like, "years ago, in the previous series of 1500's, we had this issue...traced it back to the drive shaft being shifted to a weird angle when the vehicle is heavily loaded"...apparently their (then) solution was some sort of lifting block, that solved the problem when under load but created the situaation of rumbling when the trucks would be empty

I set my Reese at 5 links....might the truck 'perceive' the load differently if I put more tension on the w/d hitch, to level it up tighter than I usually run it? that would seem to be a solution, if it's truly a 'driveshaft angle under load' issue...most times, the weight on/in the truck is the trailer tongue weight rather than a cab full of people or a bed full of heavy cargo


Thanks in advance for any further input

[Tyler0215]

U joint, carrrier bearing, CV joint, wheel bearing.