[radkawi]

Could the trans mount be faulty or failing causing the transmission and such to wobble/flop around or is it more likely u-joints or the entire driveshaft itself?
I have a 2014 1500 4x4 CC 5'7" bed with a vibration in the center of the truck. The truck now has 35k on the odometer and almost out of new limited warranty so I really need some direction. The truck drives smooth to 45/50 then a wobble to down right hopping feeling up to about 65/70 mph but it feels like it is in the center of the truck, not the front axle nor rear axle, in the center of the truck. From the front seat it feels like it is in the floor at my feet and in the seats too. From the back seat it feels like it is in the floor and under the center console. Three sets of tires, two were the same brand/model. Indexed the tires, moved them all around all four corners as well as multiple road force tire balances with no resolution or change in the ride quality. Even tried balance beads but no help. I dipped the outside rearview mirrors and watched the rear tires at speed. Tires are planted and no visible runout so it does not appear the rear end/tires are at fault from what I can see. Tire store and dealer agree it is not the tires but still offer no suggestion for resolution other than change the rims/tires and I have done both. $2k into the fix and it ain't fixed. My guess is it is in the drive line. Maybe the driveshaft spins up and is pulling the t-case/trans to wobble as it is all I can see that moves directly under the center of the truck.
I have done some research and mentioned to the dealer I found where someone posted a fix with TSB 16-001-14 drive shaft replacement. The guy that wrote the post said it does apply to the 2014/2015 1500s but dealer states not my VIN.
Crawling around under there I see the trans mount is rubber and supports the trans but nothing under the t-case so when the drive shaft gets going it could cause the t-case end along with the trans to flop around pretty good. Just an assumption though. Letting up on the throttle helps but it does not die down completely until no load/throttle under 50 mph. Switching to neutral does no good either as the shaft is still being turned by the rear end.
With all this said, could it just be that the mount is faulty or failing? The issue started at about 25k and has gotten progressively worse as I add the miles.
I found this video on YouTube and this is what it feels like but dealer said it can't be. Once launched, click the the 3 min point and watch the output house flop a bit. Thanks for any direction sir.
https://www.youtube.com/watch?v=MDq56WgBxPY

 

[TransEngineer]

I am no driveline expert, but my first thought would be a driveshaft issue (imbalance or U-joint issue). Do you have any local shops that do driveshaft balancing, that could check the balance on your shaft?

I presume your vibration is vehicle-speed related, not engine-speed? That is, if you downshift the trans to a lower gear, vibration stays the same?

Could you borrow a GoPro camera and do a similar video of your rear driveshaft?

 

[Ramdandy]

This should be covered under the 5 year drive train warranty

 

[radkawi]

Thanks to you both for taking the time to reply. I agree it should be a warrantable issue however my servicing dealer is at a loss as is the local tire shop. This issue was one present before any mods and is documented but never resolved. It was always assumed the source of the issue was the stock GYs. I knew I was going to lift and let it be for 14 months while I saved the cash for the lift/tires. Funny, didn't seem that important or irritating while I was saving but now that it is post lift/tires and getting worse I'd like to get it corrected.
Just want to make sure everyone understands that the video above was not one I shot but one found while scouring the inter-web for solutions. There sure seems to be a lot of folks across the Gen3 & Gen4 platforms that do have this issue, or one similar, however no one solution appears to fit all.
I have reached out to a local performance machine shop and will be sliding over there for an "inspection" of the driveline but not sure if they have the tools to do more than make me a new shaft as that was the first thing offered sight unseen to fix the issue. My visit will be interesting I'm sure.
I have not tried the manual gear selection, I'll try that on the way to the office in the am.
I do have a lead on a GoPro and am going to see what it reveals if I can find the time with daylight to make up something to keep it focused and strapped in place at speed. On 6 days this week with only Sunday after church to get caught up on honey-dos and such then back on another 5. With the time change it's dark when I leave for the house so it may be a few before I make any headway.
Thanks again for the input.

 

[arctichunter]

This sounds like a u-joint problem I once had. I even changed driveshafts, but, unknown to me, the same u-joints were used ( Why not...just about new.) However, after all the tire shops and 2 driveshafts, the u-joint was the culprit. In assembly, one roller needle fell into the bottom of the cup, and the yoke was stretched about 20 thou....producing the symptoms similar to yours.

To rule this out, drop the driveshaft and disassemble the u-joints; there may be a surprise waiting in there. I hope you get her fixed...best wishes....

 

[briguy]

Find a different dealer. Call customer care, and ask them for help, that way even if you go out of your initial warranty, it will still be covered, because they did not fix your issue while under warranty.

 

[radkawi]

Find a different dealer. Call customer care, and ask them for help, that way even if you go out of your initial warranty, it will still be covered, because they did not fix your issue while under warranty.

Hadn't thought about that. Will get the done tomorrow. Thanks for that tip.

 

[radkawi]

To any with this issue I finally have found a resolution. A driveline guy I visited told me my pinion angle was off, most likely off at the factory as this issue was pre-lift, however with factory rear arms there was no adjustment to be had. I recently added the Core 4x4 rear arms and with the adjustable Johnnie joints on one end. I have currently been able to set the angle to within 1.5 degree of zero and this has made a world of difference. Not only in the harmonic resonance but also wheel hop. The arms are much stronger as are the joints to which I attest has made all the difference in the previous issues I was having. I now slide along up to 90 MPH and feel none of the afore mentioned issues. I will run like this for another few weeks, check the angles again before putting in new locking nuts and Loctite the adjustments. Was a little pricey but fellas it was well worth the time, effort and coin dropped for these. Spence makes a great product and only wish I had found it earlier!