Unexplainable, Undiagnoseable, Unlocateable Flapping/Gringing Sound

I know you said it happened before the lift, but has it done it since it was new?

 

TL;DR

Suggestion- Jergens.






Good luck with this diagnosis OP.

 

Couldn’t hurt jacking up the front end and inspecting all your brake components...ie. pad, rotor, hub, abs wheel speed sensor...

 

Well since about at 6000 miles. did it several times before I installed the lift. no other mods had been done at the time

 

I agree with ABS sound, l also believe that I wouldn't have done any type of lift until I found out the problem. Unless OP is willing to let Toyota keep it for a week or two it is very possible for them not to be able to replicate the sound .

 

Sounds drastic, but you might have to mount a go-pro safely under front suspension and spend an after noon trying to replicated issue. When you do, you can show the video to dealership/ narrow down the cause...good luck

 

I had a similar sound that occured in a similar way. Check the torque on your cab mounts.

 

@Solmimi

I have a very similar situation with my 2016 4x4 automatic which started around 1,500 miles. I finally figured out what it is at 16k. My noise/vibration sounds very close to what you are experiencing, except that the noise with mine sounds more like thick, heavy plastic pieces impacting each other in a rhythmic fashion, as opposed to metal on metal. My truck will only do it at very slow speeds, no accelerator, and it usually occurs when I back out of my driveway (brake pedal operation makes little or no difference).
One day I got home and noticed it making the noise/vibration as I pulled into the garage. I put it in park and fortunately it was still occurring (almost never does it in park). So I quickly crawled underneath with a prybar and started poking around. The noise/vibration ceased when I pried against the exhaust near the right side catalyst next to the transmission.
I can say with certainty that the noise/vibration on my truck is the exhaust.

Perhaps this is something you can check on your truck, if you are able to simulate the noise. Good luck!

 

I can't thank you enough for your detailed description of your issue. I will definitely check this.

Something I could/ should add- it ALWAYS makes this sound as the front of my Taco bounces up and down, and in the same rhythm. But always with only the slightest of dips and at really slow speeds. Never over a bump????

 

OP, I believe I have the exact same noise.

It comes and goes at low speeds. I describe it as an "object being inserted into something that's rotating." Like a card being inserted into a rotating bicycle wheel. I swear mine comes from under the hood.

I recently heard that noise while pulled over and in park. My buddy's Tacoma (just like mine, a 2016 TRD Sport 4x4) was in front of me and started making the same damn noise at the same time. We opened the hoods and poked around but could not track it down (we were on the Mojave Trail in the middle of a 2-week trip).

I'd love to find the cause and solution.

For what it's worth, both of our trucks are lifted (2-3" range), and with the ECGS bushings installed.

 

I also think its your ABS, but also check the bolts holding up your center driveshaft bearing.

 

One more thing, check your calipers for the 2 brake pin retainer springs.... bent or missing

 

Stay tuned. I'm confident one is on here will figure it out. Btw, mine has never done it when in park, but your description of the sound is spot on...

 

Checked and all good. Thanks for the suggestion.

 

Brake booster pump? Its closest to your pedals and makes noises when going bad.

 

Could you tell which part of the engine bay the noise was coming from? Have you or the op checked the radiator fan to see if it's securely fastened and if any of the blades show signs of damage? Did you check to make sure your lower skid plate is secure and that none of the bolts are loose?

 

Hard to say which part. I vaguely recall the noise coming from around the engine area, but the lower part of it. I did look over all radiator fan blades and accessible/visible belts on my truck and did not see any issues.

It's almost as if there is a fan blade spinning, and something loose (like a wire) swinging into it once in a while. But I can't find anything under the hood that would match that scenario.

 

Did you notice any excessive engine movement when the noise was occurring? Maybe a loose motor mount or transmission mount...? How were your trucks positioned on the trail when the noise started?

 

I did not, but I'll keep an eye on that should the noise reoccur in park again.

I would imagine a loose motor/transmission mount would result in that noise happening pretty much non stop, no?

 

This is true, buy anything is possible...