gr8lakes

After my 2019 gx460 is parked for a few hours, i sometimes (often?) hear a rotational swishing noise for maybe 30 feet after my first or second use of the brakes.

When i hear the noise, my foot is not on thr brake pedal.

Definitely a speed dependent rotational noise. goes away pretty quickly, doesnt come back until parked again. might be associated with a left turm, but maybe not.

40k, brakes were inspected by shop and declared like new. Bought at 35k.

Is this the brakes hanging up?

If so, what should be done? e.g. grease slides, replace pins, etc.

Any parts upgrades so they wont rust and cause this?

vanduker

Are you sure it isn't the air injection pump? That runs about as you described and is in right front of engine compartment. If you want to replicate, start truck from cold, let idle for few seconds and shut off - for a second or so after engine dies you can still hear the pump.

Jacket

"swishing noise" is tough to interpret. I see you are from NY and so I assume you deal with salt and gravel on the roads. It's not that uncommon for all that crap in the snow and ice to get onto your rotors when you are parked for a while, and then "clean up" once you start driving. That might be your issue, but it would be more like a grinding/sandpaperish noise versus something swishing like a liquid.