Question about Vibration

So I have researched all over here but still stumped.

I just got my 2019 tacoma lifted at a shop that shows good reviews. I went with a 3 / 2 lift. Coilovers in front. Went all out with doing clamshell bushing, diff drop, shims on the back axle, new uca's.

Got the truck back and notice on smooth pavement between 40mph and 55mph I feel a mild vibration thru the front floor / pedals and little in steering wheel. Put it in 4 high and goes away. So from research it shows the clamshell bushing. The shop said they did that and sent me a carrier bearing spacer. I installed and it still has the vibration. I called the shop and brought it back to them.

They said it sounded like it could be a bad clamshell bushing they installed and they replaced it. They also took the diff drop out and drove it then put it back in etc. I test drove it with them and the vibration was still there but I can say it was better but not fully gone.

The shop said during this second visit they checked the castle nut to the hubs? And the factory had them torqued way too tight so they torqued them to spec. They say its either that or the new tires need breaking in etc. Im have new k02s.

Does anyone have suggestions? Could it be their wheel balance was bad but only between 40 and 50mph? Or a bad wheel they are not telling me about? And that castle nut please educate me but wouldn't they have had to remove it during the first time they replaced the clamshell bushing?

Guess im just confused as the truck had 20,000 miles on it before the lift and no vibration.

I also totally understand a lift will never ever ride like stock. I just want to make sure this light off and on vibration isn't wearing my diff out etc.

Thanks everyone.

 

Sounds like the shop is taking a shotgun approach on the vibrations. The carrier drip and/or shims may but even be required. You need to take some measurements on your pinion angle and transfer case angle at the flanges and determine if you need shims/drops and experiment with the right size of each.

castlenut sounds bogus, tightening too much will cause a shortened wheel bearing life but no vibration. Did the shop provide torque values for “too much?” At this point I’d be losing my confidence on their knowledge or how to install parts and diagnose issues.