vroom vroom on passenger side ? ?

Every morning, I get in my truck, crank it up, stick it in reverse and I hear this soft, quiet vroom vroom. Sounds like it's coming from the passenger side.
Doesnt just do it when in reverse, does it also going to drive but only when I first start the truck and procede to go.

Anyone have that ?

 

do a search: it is some brake pump priming or something. mine only "vrums" once.

 

Yeah, it does it once mostly but I do hear it twice sometimes.

 

normal....annoying, but normal.

 

its normal, its the abs self check