Yesterday, I pulled a 34' tag w/ 2 Jeeps on it ~100 miles east for a day of wheeling. No problems at all. Coming back, the wind had kicked up something fierce. The truck was kicking out of OD and was running long stretches at ~2600 RPM and 36-39 pounds of boost. Pretty consistently, but not always, the truck would make a high pitched hissing sound that sounded like a boost leak but it held boost fine. At lower boost levels it sounded normal.

My truck:

2005 automatic
119,000 miles
BHAF and de-silenced intake
5" turbo back w/ 51" Donaldson
Quad box (noise happened stock and +30HP setting)
Quad Commander for gauges (uses OEM boost sensor so it maxes at ~40 PSI)

The truck pulled GREAT, but I'm a little concerned that something may be wrong and it'll turn into a problem. A buddy suggested that there may be a problem with my wastegate. If that's a possibility, I'd appreciate it if you could point me toward a resource to tell my how to check it out.

Thanks, Scott

 

Exhaust gasket possible, check exhaust gaskets on manifold. Soot would be tell tale sign. Most likely #6 cylinder exhaust gasket.