I just installed the PAC Brake on my mega cab. Its running well, except for a shrieking noise that sounds like its coming from the exhaust brake or the turbo or somewhere in between. I understand the low rumbling noise the brake makes when engaged, and the sound of the backpressure, but this is a shrieking or whistling noise that emits when decelerating from 60+mph to 25. I wonder if its coming from where the turbo meets the exhaust brake's elbow. I was going to take it off and inspect where the edges meet to ensure a clean connection. Since the noise only sounds when the brake is engaged, it makes me believe it is north of the valve. It can't be normal as the noise is quite loud. Almost like a power steering belt is loose...that high of a pitch. The pitch starts high, then as I slow it gets quieter and lowers pitch.

Thanks for any insight you can provide. I'll post pictures and some info/troubles with my install.

 

You have a small exhaust leak between the brake and exhaust aminfold somewhere. A manifold gasket, turbo mounting gasket or the connection between the turbo and brake. Since you just messed with the brake, I would guess the connection between the brake and turbo has a slight leak.

If you want, when the manifold and turbo is still cold, you can get some soapy water to check for the leak.

 

the leak is coming from the turbo/manifold joint. IS there a gasket there? The old soap and water work everytime. I guess I just assumed it was the brake. Any ideas?

 

Start tightening stuff down to see if that stops the leak.

 

PROBLEM SOLVED! I started tightening all bolts and came across a nut that wasn't there! The manifold has 2 loose nuts. The noise was air moving through the manifold gasket!
The missing nut holds down the heat sheild,so I'll replace that shortly.
Thanks for the help!!