GX 550 Luxury Plus Rear End Noise While vehicle off

[capage01]

Picked up my GX 550 Luxury Plus just before Christmas and overall I've been pleased with the truck. There is one strange issue that I can't seem to find posted anywhere and that's a rear-end noise when the vehicle is parked and turned off. It doesn't happen all the time... just sometimes. Most recently I got back from a modest drive... vehicle parked in garage for a few hours and I go out to get something and I hear this whining sound... its coming from somewhere in the rear-end. Any ideas or thoughts as to what this could be? I can't pinpoint exactly where it's coming from...and why some sort of pump would be running... but its loud. Video attached.

New to this Forum... this is my first GX... Please Help!

 

[Nabbz]

I believe that would be the gas tank vapor pump (EVAP system). Car Care Nut on youtube had a vid about that sound that equalizes the tank pressure after it sits in the garage for a couple hours.

 

[capage01]

Thank you for the reply. This could make sense and is in the location of where that evap system is after some additional digging. Possibly there is some details in the manual about this as well.. i haven't been through it all yet. Thank you again!