Strange Sound. Is it Normal?

Lately I’ve been hearing this strange sound, it sounds like something is getting pressurized or releasing pressure, I can only hear it shortly after take off when I first start my truck in the morning, sound doesn’t seem to appear again if I have been driving. I can’t pin point exactly where it’s coming from but it’s definitely coming from under the truck front side area. I recorded a small video, you can hear the sound at the very beginning at around second 3 then it stops, y’all may need to turn the volume up, can be heard better with earphones. I have never heard this sound so I’m wondering if any of y’all have experienced this, I did recently replaced rear brake pads but don’t remember hearing it after the job was done.
https://youtube.com/shorts/K57dpF2bpzE?feature=share

 

Probably secondary air injection. Turns on at startup when it’s cold outside.

At some point it will fail and Toyota will want $4,000 to fix it.

 

Has to do with the abs self check, its a deep, loud, thud/bonk.
. My 2018 SR5 does it too. Ive read a thread about it but can't recall what exactly does it but its every time you start driving after you start up the truck. Nothing to worry about.

 

My 04 does that every time I start up and begin to drive away. It has done it since it was new. It has to do with building brake boost pressure, but I don't know exactly how it works. It won't do it if you just start up and sit - the car needs to be moving. No air injection on the 04.

 

Didn’t catch it was an 04’

 

We're multigenerational, bro

I'll add that it only happens in Drive. If I start up and reverse out of my driveway, no sound until I put it in Drive and go about 5 feet. It talks about it in the manual.

 

I’m familiar with this, it doesn’t sound like a thud/bonk type sound, it’s more of a hydraulic liquid type sound, and it’s not very loud.

 

That may be it, it does only happen in drive never in park nor in reverse. I just don’t ever recall hearing it until recently.

 

It's not a thud, it sounds just like your sound clip. It reminds me of a clock spring unwinding quickly.

 

Coolant level ok? A/C off?

 

https://www.tundras.com/threads/dealer-said-my-clunking-noise-coming-from-abs-actuator.4832/
thread on here just to confuse more people. If you think its serious get it checked out. I throw it under the overthinking category and move on.

 

Not sure if you have VSC or not, but they both make noise, which is normal. From the 2004 Toyota Tundra Owners Manual:

 

Coolant level looks perfect, doesn’t matter if AC is on or off i still hear it.

 

Awesome! I was able to find it on my manual last night! That could be it, I just have never heard it before and I don’t remember ever hearing it till recently. I wonder if there’s something going on with my steering rack, I will continue to inspect and come back if see something weird.