Hello, I have a '02 F150 XLT 4x4 Supercrew and everytime I floor it and it shifts into 2nd a strange little whistle comes from somewhere, but only inbetween shifts. Anyone else know what I am talking about? Sounds like something might be loose anyone know?

Thanks

 

Do you have an aftermarket CAI or a throttle body spacer??? A lot of the spacers make taht same whistling.

 

ya my truck does that too. i have a transgo shift kit in mine and when it slams into second i hear a whistle coming from under the hood. My friend thinks it could be the belt that is slipping.

 

How loud is the whistle? At WOT I have a howling sound which I am pretty sure is the fan clutch. I just bought one to replace it.

 

mine does it to.. its either the gear synchro or the tensioner pulley bearing is going out.