question no. 1

[tankyanker]

hearing strange sucking(?) noise when i let off accelerator to downshift in hard pull. dont hear it when i'm going through gears or giving it throttle, but if i'm pulling hard loaded into a hill, i hear it briefly (but noticeably) as i let off the pedal quickly to downshift. checked all the red and blue intake hoses, and everything seemed ok, but continue to hear sound. should i go back and check them again? could it be somethin in the CAC, or the wastegate in the turbo flapping?

[pdm]

What is the year & make of your truck & engine? The more info the better, has any work been done to it recently, etc

[tankyanker]

2000 frtlner classic, c12, no recent work

[Papa Rick]

Just had my Turbo Gasket go out yesterday. Mine started 3 days ago making a sound only when it was winding out loaded above 1500 rps, and then when I let off the pedal and the Jakes would kick in.

When I let off of it it reminded me of a old farm tractor. When it started it was barley noticeable, but then it got louder each day and I could not find it, until yesterday.

Put my hand around the turbo gasket while running (BE Careful that dude is hot) and found the air leak.

Mine is a C-15 Cat.