Weird "bouncing ball" sound

So, I just bought my first Tacoma last week. It's an 06 with 123k miles. So far I love it and already have a laundry list of mods I want to do... but first I want to work out the small things. One being a strange sound that I can't identify.

I have been hearing a weird sound coming from somewhere behind the driver side of the cab that I can only describe as a hollow bouncing noise... like someone dropped a wiffle ball in a bucket from a short distance. It's always nearly the same sound, and happens (that I've noticed) when I'm below 10mph and I jar the vehicle, either from tapping on the gas pedal or going over a bump. I was once able to recreate it by closing the driver access door, but only once. I can't figure it out for the life of me and it's going to drive me nuts eventually.

Anyone have any ideas?

 

sway bar bushing in the front possibly

 

What size cab do you have? Do you have seats in the back with storage under them. It could always be something simple like something bouncing around the storage compartment under the seat.

 

Does it sound like this???

https://www.youtube.com/watch?x-yt-...yer_detailpage&v=iSznOEq6CG4&x-yt-cl=84359240

 

Looks like he has an AC. Stupid question, did you check the bed pockets?
Does it only happen on bumps and acceleration? Or does it also happen on braking?

 

Oh man, that video.

So the sound isn't as random as something bouncing around in a bed pocket. I guess a better way to describe it would maybe be a flap on a spring? It makes the sound for about a second and a half each time, and sounds exactly the same each time. Bop......bop.....bop...bop.bop.bopbopbop.

I'll try to get some audio. It sounds like it is either echoing from somewhere right behind the cab, or somewhere inside the back wall of the cab.

It seems to not happen on braking. Mainly bouncing around offroad (my rough gravel driveway) or moving under 10mph tapping on the gas to lurch forward a little, or going over speed bumps.

 

Check the rear shocks, might be a loose bolt or bad bushing

 

I figured it out... There's a rectangular plastic piece that looks like it pops into the cab right in the center, below the level of the bed. It's making the noise. Now I just have to figure out how to pop it back in place...

 

Cab vent?

 

Hope you found it. I get a similar nose when my passenger side seat belt clasp bounces on the side frame.

 

I had a similar issue with my Camry,mfound a golf ball under the seat lol

 

Now I want these noises... my truck don't got none...

 

Yep that was it. No golf balls or well endowed women.

 

My Access cab did this when I bought it new in 05. Only when it was really cold though. Turned out to be loose rear cab mounting bolts. I pulled the nuts off, put a washer on each bolt, and tightened it back up. Never did it again.