Technical vibration question

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.

 

Might be time for a Tom Woods one-piece driveshaft. Lucky for you, they are in Utah.

https://www.youtube.com/watch?v=fsNB0HQPxvw

 

I thought about this but all of my research says if I am feeling the vibration in the front then its not driveline related. If I felt it under my seat then absolutely. But in my case I am not. But please correct me if I am wrong.

 

OP I feel for you. My 2018 was lifted with Zero miles on it by the dealership and at 46-49 MPH I have had a ridiculous vibration coming from the rear end. They have looked at it so many times they just gave up and so did I. Parts replaced, wheels rebalanced and again and again. Various other things I don't even remember them all. They still to this day say it's the aggressive tires on a really smooth road section that sets it off. I try and avoid nice roads (not kidding) or avoid that very specific MPH, again not kidding. I will say with a bed load or towing a travel trailer I don't seem to notice it as much but myself and Toyota guys have chased the rabbit down the holes too many times. Speaking to others with lifts it seems as if it is hit or miss if you have any vibrations at speed.

 

Thanks I appreciate your response. In the end I guess I might just have to not pay too much attention to it and just understand that if something wears out its just part of having a lifted truck. I just hoped it would stay with common stuff like ball joints, tie rods etc and hopefully not front or rear diffs. But you make alot of sense so thank you.

 

Yeah I cant really see how you would pull a CV from the diff without also pulling it from the hub. Did you see them do the bushing yourself, or see evidence of it? Like maybe some wet spots from spilled gear oil?

What degree shims did they use?

Did you get the tires road-force balanced, or just a regular balance?

Im tempted to say its a driveline issue (loose carrier bearing, bad u-joint angles, etc). But the fact that it goes away in 4WD seems to disprove that idea

 

No I wasn't there as I dropped it off and picked it up. They stated their quality control was perfect and they have to sign off on everything etc. But there just seemed to be flaws taking 4 times to align it with test drives. Maybe thats normal idk? Then to me atleast they forgot the clamshell bushing the first time as im not sure how they would put in a defective one? But again im no mechanic. Guess my biggest concern is when they said it must be a factory issue as they don't remive the castle nut to the hub while replacing the clamshell bushing? I think they do so this 2nd time they said they replaced the clamshell wouldn't have the over torque been from them the first time?

Idk I am not one to speak out against mechanics as I am not a mechanic. Part of me says maybe I dump another 800 bucks into a different shop and have them look over everything. As far as shims go they said they use the appropriate degree of shims for the 2 inch lift in the rear. The rear is 2 inch blocks and they are shimed blocks. Yes I know I did right in the front with coilovers and probably not right in the rear going with blocks.

 

I say mabey the BFGs as they are known to be a high maintaince tire and always need balancing or you may need the tsb for the shifting issues or gear hunting issue and maybe a KDMAX tune. That 45 to 55 mph gear hunting or confused torque converter may be it, just a guess. Also run a lower air pressure and mayby switch your stock wheels and tires back on and see if the problem is still there. These are all a guess, but also check the torque settings on all componets, and sometimes an issue in the rear driveline and be felt up front and may lead you to think its front end related. Hope this helps and good luck. Maybe try a rear carrier drop too. I have a bilstein 5100 lift and a block, the shop used front diff and rear carrier drop, ecgs bushing and no vibrations.

 

Yeah thats what I was getting at as well. Assuming they are talking about the CV nut, and assuming the person talking to you was describing it correctly (which might not be the case..)

But either way as I said before should be easy enough to take a quick look at where the drivers CV goes into the clamshell, see if you can spot the fresh gear oil spill

 

I will check that today. Thanks

 

I suspect you have a harmonic vibration being set up in the speed range of 40-50 mph.

This is likely due to tires. Suggest to try another set of tires that are not KO2s. If the vibration goes away, then you know the problem is related to the tires. If the vibration remains, then the problem is related to the 3/2 lift.

Try some isolation techniques to narrow the focus.

BTW, never heard of the need to "break in the tires". Sounds like BS.

 

I’ve definitely had vibrations noticeable in only certain rpm ranges caused by mud/snow in the wheel. It’s the nature of vibrations. They can have a resonance at a certain frequency that causes the amplitude of the vibration to peak sharply.

 

If it were tire related why would it go away in 4WD??

 

Different rotating mass. Front prop shaft and xfer case.

 

This is just a guess, but engaging 4wd could change the resonant frequency.

 

Unless one of OP's front tires is off the ground 4WD shouldnt matter as far as the tires lol. All will be spinning at the same speed regardless of 2x4 or 4x4

 

As @gudujarlson said, that I neglected, the additional rotating mass may change the resonant frequency.

Vibrations are not simple things to solve or diagnose, but in concept are fairly straight forward.

Every object/system has a natural frequency. When an excitement (think a thump) occurs near the natural frequency a harmonic vibration can be set up. This natural frequency is dependent on the mass and stiffness of the object/system.

Look up the Tacoma Washington Narrows bridge failure, the video is quite dramatic. In a nutshell, the wind set up a harmonic vibration and the bridge collapsed. When the cause was studied, the design of the bridge was changed to increase its stiffness and mass. This is just one example. Music is filled with harmonic vibrations.

In this case, it could be the tires that are providing the exciting thump near components natural frequency. Changing to a set of tires that are NOT KO2s could remove the exciting item, the thump. If so, then the solution is tire balance or different tread pattern, IE different tires. If the vibration persists, then the problem is in the lift components.

 

Wider deeper tire tread looks good, but at higher speeds, they start grabbing and trapping air, that is pushed back to the road and out. this equalls vibration and why people always have issues with them.

 

A buddy of mine with a 2019 trd did a 3'' lift on a new truck with no miles...end result....lots of vibrations at those speeds mentioned. After a year he decided he's had enough of looking cool at the shopping malls its back to stock and much happier with his truck.

 

Another possibility is the change in dynamic toe and overall alignment. RWD toes out; FWD toes in.
I'd be curious to know OPs wheel/tire specs and alignment numbers.