Ford 6.0L Power Stroke Diesel :: HPOP Making Noise / Sound Is Prominent At 1400 RPM

I've got a noise that I just can't find. Have replaced a bunch of stuff trying to eliminate this sound.. steering pump, both front wheel bearings, new pads up front, both caliper brackets and pins. Did a new turbo, verified the new pump is not air bound, brakes work, no noise with wheels up, lock to lock, pumping brakes the whole time.

Sound is prominent at 1400 RPM, does go up with RPM, seems sometimes to follow a steer to the right. When I shut down, not at full temp a clunk happens, like a mechanical stop. That clunk is less noticed once up to temp and it really started after the steering pump. Sparky came over, listened with a probe, says it's not the pump, my BIL and a close friend say the same thing.

Today, when I nailed it, rpm came on hard, tires smoked and when I let off quick, truck died, like something held the belt. It just slowed and died, restarted immediately.

Shawn listened to the transmission, says he heard nothing there either but did hear something above that near the back of the motor.

IPR is spot on 21.8%, ICPV is .80-.82 and [email protected] However, it has been dropping to lower numbers recently, saw 15.4% and it often sits near 19.4%-20.4% for periods of time. Tap the throttle, right back to 21.8%.

I'm at a loss. I've tested everything I can think of. I can power brake the truck, no trans slippage, it spins the tires easily around 10lbs boost. The A/C seems low on the charge, it is freezing the dehydrator and I added some freon, 18oz can, the clutch is not frozen. Turn it off, compressor stops spinning like it's supposed to. The tensioners are not frozen or squealing, water pump is not making noise, temp is 200 on the dot. Trans is full, no burned smell. Motor oil is fresh, filters clean.

It sounds like a grinding noise and I'm about to tear the cover off the HPOP. I'm at 150k now and know it will need replaced soon, I've spent $2500 in the last 2 weeks, but before I tear it apart......