Whistling cab noise

[StevenN]

Just purchased a 2023 Seneca and found when driving above 35-40 mph we get a loud whistling noise. It’s not rpm related so it’s not the turbo, checked the windshield seal as well as the doors and can’t find nothing. I hope this is not normal lol. Have anyone else had this problem? It’s seems like wind interference of some sort. Thanks

[Jeepin Jason]

Try putting tape or plugs over the holes on the side mirrors and mirror mounts. That helped a lot on my rig. If that does not fix it, could be air coming through the space between the cab and the bunk. A guy on Facebook stuffed a pool noodle up there and said it made a huge difference. I am going to try that with pipe insulation that is already black and see how it works.

[Rustynuts]

A quick search in this forum for “Cab Noise” or “Wind Noise” will net you dozens of threads about the problem and many solutions.

[EricM22]

I have had my mirror holes plugged for some time, and despite never having whistling, it started a few weeks ago. Turned out the slideout seal on the top of the drivers side slide worked its way forward about 8 inches, and was causing the whistling. Pushed it back, secured it with a screw and washer, and the whistling went away. I've heard those “wandering seals” are a typical problem with these rigs.

[CAG]

I will put this out there although it might not be the issue.
I had a windshield replaced, three times, because of a whistle at 65 mph that finally, they fixed with an OEM windshield. Not saying that is your problem but these Chinese glasses are bad!

[Plumberman]

I am looking into the windshield whistle as well. We stopped at a truck wash in Amarillo last summer to get the bugs off. I was sitting in the cab when they rinsed the cab/windshield and water shot in through the bottom corner gasket on the windshield. Going to do some testing with air before taking it to Freightliner. Unfortunately I generally have to do the trouble shooting and then tell them what needs to be fixed.