Can anyone help me with this whistling noise on my truck it’s a kenworth T680 Cummins, it comes up only when accelerating and when I try to slow down on hills, or when I use my engine brake No noise with constant speed or cruise controlI attached a link with a video of the noise Please help me out https://youtu.be/vrkCy5cxs1A
Leak on intake manifold or charge air cooler. Learn how to check the system with a few items. 5 inch pvc end cap, hose clamped on intake tube off of the turbo drill holes to screw in pressue gauge and valve for adding air like a metal tire valve stem, also block end of tube at the intake manifold with 5 inch pvc cap, secure with hose clamp, pump air into system 20 lbs, see how long it takes to leak down. You have a leak somewhere. If you can't find it, hook up the end to intake manifold and repeat. Could be leaky gasket on manafold or hose going to air compressor. Good Luck.
