Strange sound under load

[J D Young]

When pulling an 11K trailer, WOT, & I let up on go petal, a strange sound comes from the turbo area. Sounds like the filter housing is collapsing or something. I've checked all the hose clamps, they are tight. Does not happen unless I have a big load & WOT. Any ideas? She is a 2001 QC auto w 3. 54, 3000 mi.

 

[TXRam]

Hey Jimmy,

What is happening is you have all that boost at WOT and then you let off the accelerator and there is a huge reduction in the amount of exhaust gas to power the turbo, and the turbo will actually reverse direction. This is normal, but not very good for our turbos - it can break the shaft, alot more likely on modified trucks though.