Swish swish rattly sound with tranny

My 17 Tacoma SR with automatic has started to make a swishing noise that changes into a rattle when driving it. I suspect the transmission, but it seems to shift fine except for the chatter. I am hearing impaired, so I am not entirely sure. I took it to the dealership, but they said it is out of warranty now, so I won't let them touch it. They did say to check the heat shields around the exhaust which would make a similar rattle sound. I did and they are all good.
This truck only has 30000 miles on it. At first this noise was apparent when I first left the house and went a block or two and then it went away. It happens every time I accelerate now. Just driving at steady speeds, it does not make any noise.
I don't think it is brake related but plan to check those tonight to make sure.
Anyone else have this problem or have any suggestions? I'm lucky enough to have a mechanic in the family to work on my cars but I try to fix them myself when I can.

 

Is anybody there?

 

Hi, have you checked your oil level? And have any lights popped up in your gauge cluster? If you're hearing liquid swishing then it has to be something fluid related I assume. I don't think it would be the brakes if you're hearing it under acceleration though.

I would double check the oil level for sure. Is it possible you have any tanks of water in the car somewhere that are swishing around?

 

A freely given opinion from some rando on the internet is not the same as an in-person one from a mechanic. These weird noise threads rarely end with a resolution. There is a small hope though! You need to provide more info. Start with a video or audio recording of the noise.

 

Check motor and trans mounts, maybe hanger bearing mount, just sounds like something loose under there.

 

Hi all,

It turned out being one of the heat shields on the catalytic converter itself. One bolt rusted away and it was vibrating against the converter. The shield was fine. I didn't catch it because the shield appeared to be tight but it was a different story when my nephew shook the exhaust. This is a common problem I am being told. Dealership said they have seen several come in like that. We fixed it with a stainless clamp. You can replace the bolt but we figured how long would it be before the other bolts rusted apart. The noise this made was unreal. While the converter was cool it was loud until it got hot and then quieted down.
Try to remember this because more than likely its going to happen to you as well with rust belt Tacoma's.
I was also concerned at how much rust my 17 had on the floor boards compared to my 13 Sienna which has no rust underneath. I pressure wash it after every snow but it didn't make much difference except for maybe the frame which is clean. While underneath I also got to see up close the crappy rust protection job my dealership did during its recall. Half assed is the best way to describe it. I dont drive the truck in the winter anymore so it should not rust anymore.