So I have searched and searched for a thread with my same symptoms with no luck.

Truck has a funny buzzing/vibrating sound that kicks in around 1500 rpm and gets the loudest at 2000 rpm. It almost sounds like a hydraulic whine. Above 2000 rpm it drones out due to the straight pipe exhaust. I have ran the truck up to 2000 rpm in park and the sound is still there, so I assume its not transmission/ drive train related. I cant pinpoint the location but from in the cab it sounds like its dead center of the engine compartment.

Anybody ever had anything similar? Maybe turbo related?? Thanks in advance.

 

check my thread "electrical noise under dash" see if you think your situation is similar.

I think it's still on the first page here

 

Does "straight pipe exhaust" include an aftermarket downpipe? Perhaps it's hitting/rubbing the firewall.....

 

I looked at the thread, the only thing is my brake light isn't flashing.

As far as the downpipe, Ive been running that exhaust for a while now, thought I gave the pipe enough room when we put it in, but its worth checking out..

Thanks for the quick responses!!

 

well my brake light didn't really start coming on until the end, probably the last 5-10 miles right before the pump crapped out... might be worth checking out to.... other thing could be up pipe leaking, I haven't heard it described that way but if the leak isn't very big i suppose it could make a different sound than if say half the doughnut was blown out or vice versa ya know.... just a thought.

 

I agree. My first thought was the turbo, maybe the bearings getting old or the EBPV sticking

 

There was a TSB issued for moaning or buzzing at 1500-2000 RPM and it called for replacements of the motor mounts. I say this but only from memory. I could very well be wrong. I'll try to pull it up tomorrow.

 

Here ya go.

https://www.ford-trucks.com/tsbs/ful...tsbno=03-21-26

 

Also check the intake boot where it hooks to the turbo. Make sure it doesn't have any tears or holes in it.

 

So I found the culprit. The edge of the downpipe clamp was just barely touching the transmission housing. But it was almost impossible to see without getting under the truck and having it ran up to 2k RPM and watching it buzz against the housing. A few crowbar adjustments later, no more buzz!

Thanks to everyone who posted replies

 

Cool! Things like that sure can drive you nuts can't they! Glad that's all it was.