Intermittent vibration through the floorboard

I installed my 5100s on 1.5” in the front, 5160s in the rear. Started to get intermittent vibrations through the floorboard, so i did the ECGS bushing. This did not take care of the issue. If I put it in 4wd the vibrations go away, but I already did the ECGS bushing? This is where I am lost. If it was another drive line issue it would persist in 4wd, but it does not.

Now i have a full leaf pack (adds 1 inch) and the vibes are the same. Also it was going on when I had stock tires.

I dont want to create another thread, but I have not seen others with these symptoms.

I followed the instructions to a T, the CV is seated correctly, truck has proper alignment... Im at a loss.

I may try a carrier bearing drop, but I don't have high hopes as like I said it goes away while in 4wd,

thanks in advance.

 

maybe need shims

 

Many would have said you need ECGS bushing . But you already installed it. Are you sure it’s installed correctly not too deep or too shallow ?

 

I would guess rear driveline vibe. I had it when I lifted. It would vibrate on deceleration when the brakes caused the weight shift which extended the rear shocks and caused rear driveshaft angle problems. I installed rear axle shims and the vibe stopped. Good luck with the Lift Gremlins.

 

Yes I spent around 20 minutes making sure it was perfectly flush with diff, installed the correct way, put it in the freezer prior to installed and used a light coating of diff oil to help with install on the outer surface.

 

Even though it only happens in 2wd?

did yours also go away in 4wd? Thats where i am stumped

 

I have not replaced them, but I cant imagine they would be bad. Noise started right after install of 5100s and the truck only had 18k miles at the time

 

Thanks to all who tried to help. It ended up being a warped rotor somehow. Since everything was at the correct torque, I decided to start with the rotor first, then if that didnt work make my way to the hub bearing. Very odd that it went away in 4wd, but I guess you never know.

 

Mine is doing this on a bone stock truck. It feels like when rotors shake a vehicle under braking, except there is absolutely nothing coming through the steering wheel so you can tell it's not the front brakes. I was leaning towards drive line when the nose dives, and I think you've confirmed it.

It's a new truck, so I've been trying to figure out how to reproduce it on command, so I can do it once the stealership claims they can't feel it... It's speed dependent as well.

 

Sounds the same as when my 2020 tacoma was like when it had under 1500 miles. It had a very slight or shutter when coming to a stop. I slipped the auto transmission in neutral, and applied the brakes when coming to a stop, and it was gone. I now thought it could be a converter causing it. Well, over the next thousand miles it gradually went away, and hasn't come back. In fact the transmission just got smoother, and shifted better when it had to. Truck is a joy to drive now.