Vibrations while coasting at 15-30mph

My last thread I made on this topic seems to be dead, so here’s my attempt at reviving it. Have not been able to figure it out. Made a post on Facebook and I’ll copy and paste it here:


“Alright guys. I seem to be in a bit of a pickle. I’ve used the search feature and looked over the forums but I can’t seem to find anyone with this specific issue I am having.


I know I’ve posted about this before (might have deleted it, can’t remember) so bear with me.


I am getting a rumble/vibration from what seems to be the front end from 15-30mph. Anything over that it is buttery smooth. Does it in both 4x2 AND 4x4. I bought the truck with around 40,000 miles (with no lift) and has done it since I bought it. After installing the lift I believe it has become more noticeable.


I have ruled out: transmission, as it does it in all gears - haven’t tried reverse, but the actual shifting is smooth and it rides just fine. U-Joints on driveshaft are solid. Front diff, as I have already installed the ECGS bushing fix, but that does not seem to have fixed anything, so I am looking elsewhere. I believe the first week or so with it installed was pure placebo, I don’t doubt it’s a good product, it just didn’t fix my issue I am having. If anything I’m glad I had it done for future proofing. My CV boots are not torn or leaking anywhere, and they don’t have any play in them, so I’m not really sure where to look. I don’t suspect my wheel bearings, as highway speeds (55-75ish - I drive like a grandpa) are quiet, and all I can hear is slight tire noise from my Toyo R/T’s.


It is more of a vibration than it is an audible sound, but it is audible if you are really paying attention to it. It starts around 15mph, and seemingly gets to the worst point around 22-25mph, then tapers off at 30. Highway and moving the truck around under 15mph it is completely silent. Happens when coasting, accelerating, and decelerating. Engine vibration and noise drown it out for the most part on acceleration, but on deceleration and coasting it’s very noticeable with the A/C and radio turned off. Gets much more “rumbly” when I take turns, and slowing down to a stop. Once I am under 15mph the noise completely disappears. At this point everytime I drive my truck it’s all I can hear, it’s driving me nuts to the point where I’ve considered trading it in. Incredibly frustrating, I am coming from a 1st gen sequoia that I built up the same way and never had any problems like this with it I’ve had it looked at by one of my local dealers soon after I bought it (Not the dealer I purchased from - BEFORE I had the lift installed, and when I was still within warranty) and they just told me it was my tires (at the time they were stock size Goodyear wranglers) however now that I have bigger tires on it is seemingly much more noticeable.


Going to rotate and rebalance the tires this next Wednesday to see if that helps at all. Fingers crossed that’s what it is”

 

sounds like a tire issue, I have had a similar issue with AT tires what air pressure are you running, because it gets more noticeable with speed I would think it has something to do with the balance or harmonics of the tread hitting the pavement, lower the pressure and see if it changes, if lower tire pressure gives you a noticeable change that would point to a tire issue, I would lower to 30psi just to test.

 

I currently run 42psi. I’ll give 30 a shot and see how it sounds.