So, like my 16 before, my 18 also has a vibration. Already eliminated wheels/tires, was hoping that it was that easy, but since it only happens between 48 and 55 MPH, and on new smooth roads outside that range, the truck is silky smooth. Since it is RWD, my guess is a couple items, first of course is the drive shaft, however, with a load in the truck, the vibrations are still there at the same speeds, ruling out pinion angle. My second guess would be driveline harmonics, where the combination of gear selection, engine RPM, and torque being applied is causing an imbalance that is felt, and heard. It is a low frequency type of vibration felt throughout the truck, in the seat, steering wheel, floor, but funny enough, not in the gas pedal. There really isn't much else that can cause it either. It goes away when I remove power, comes back the moment I apply power, and only between 48 and 55. If I lock out to 7th, I think it goes away as well, but need to verify that as I think it only occurs in 8th gear. If only 8th gear, could it be the transmission? I don't know enough about it to know what parts are moving internally that could be out of balance.

Has anyone been able to come up with a way to diagnose a harmonic imbalance like this? Where would you even begin? I know one thing, not going to waste my time bringing it in since the hard *** techs never feel vibrations.

 

Just a hunch but have you looked at you transmission mount? I would think there should be something to damper/isolate it from the frame. At least be sure all bolts are tight.

 

I read the threat title....saw the poster and thought "oh no, not again, this has to be an old thread". Not cool.

 

Sounds just like my 2016. Mine's a CC, XLT, 4x4 with 2.7. Very frustrating, dealer says it's normal...

 

 

Diaper over the oil pan on mine was buffeting bad.....long story, took it off and vibrations gone.....dont know if you have one or not but its a quick easy thing to try.

 

Oh my god man.... I have followed every thread you have made I feel for you... I wish I had something helpful to post but I can only offer my condolence..

 

Nah guys, no worries, I love this truck and the vibration is so minimal that I only notice it on certain roads only if I am under 55. I would like to get to the root of it to make an almost perfect truck perfect. I swapped out the tires and wheels I had on the 14, then the 16, which the tires I bought last year and have 20K on them, and going over tracks now, barely notice them. Truck rides, steers, accelerate so nice and is so comfortable that I must get to the root of the vibration if only to satisfy my curiosity. Unlike the last one, this one steers so straight that it is constantly dinging for me to put my hands on the wheel!

This one FEELS like a new truck! That last one never felt like a new truck and only got worse as it aged.

There is a place not too far away that specializes in drivelines, and may give them a call to see what they think.

Lets just say that I like this truck so much that I want to go for long drives now, it reminds me a LOT of my 2014, and missed that truck greatly until now. I got my Precious back!

 

I don't want to sound stupid but what is a diaper? I am assuming a skid plate but I am not sure.

 

Does it have the electronic locking diff? If so have the cover pulled and check out the carrier. Mine was very sloppy causing a vibration..