Suction or possibly vacuum noise on passenger floor board

[Sarge792]

When I first start driving my 04 2500 4x4 and it shifts from 2-3 or 3-4, I hear a suction then a small clunk on the passenger floorboard. This is in the area where the turbo is located. I have checked the clamps for turbo and everything seems fine. Any ideas of what to check next? Thank you.

 

[SnoKing]

Something in the HVAC system? Chris

 

[Sarge792]

I don't know, someone mentioned some type procedure switching 2 hoses from heater core? Has anyone else heard of something like this?

 

[jhenderson]

Sounds like it could be the recirc door in the HVAC system. Try cycling the control from recirc to fresh air. If there is no change the door is broken and probably flopping back and forth under acceleration.

 

[cerberusiam]

Does it make the osund every time no matter how you are driving? Sounds like that in the neighborhood of the turbo usually indicate turbo bark or surge, especially on shift points.

 

[Sarge792]

I usually only does it once, shortly after starting & driving. I have noticed now that it is more near the shift that than it is any other time.

 

[Sarge792]

if it is the turbo, what should I do to fix this?

 

[Bob4x4]

Turbo is not going to make a clunk in the floor board.Have a passenger place his or her hand on the hvac housing and do what you can to reproduce the noise.Also check to make sure the trans dipstick is not resting against the heater hoses.