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Monaco Wolfy · 05-09-2019, 10:17 PM

I've noticed lately a new noise that happens sometimes when I let my foot off the gas pedal with the exhaust brake on. Usually more noticeable the first four or five times engaging the exhaust brake, then the noise slowly lessons somewhat after that. It's hard to describe, but sound like something rubbing for just a 1/2 second when the exhaust brake just begins locking in. It sounds like its up front, under the floor. It sounds like a metal shaft or something metal rubbing against a rubber surface, if that makes any sense. No noise once engaged. Any Ideas?

Skip426 · 05-09-2019, 10:31 PM

I'd say a very close look at the exhaust manifold is in order, either a cracked manifold or a blown gasket ; at the cylinder head or the turbo mount flange.

hardy1000 · 05-10-2019, 08:30 AM

Had a noise and it was a cracked exhaust manifold. Had it replaced last year at Cummins in Missoula Montana $1100.

Monaco Wolfy · 05-10-2019, 08:36 AM

The noise is front the front end, not the back end. That's what has me puzzled. No visible, notable issues with the manifold that I can see.. Does anyone know what is under the front floor that moves when activating the exhaust brake?

Timaz · 05-13-2019, 01:11 PM

Have you checked the front suspension for rubbing? Weight transfer when you go to the exhaust brake.

gweedo295 · 05-14-2019, 07:36 AM

You'll know when its an exhaust leak, it's usually a loud screeching noise, mine did anyhow. My manifold gasket blew last year and luckily they were able to surface the manifold. Good thing I have the Good Sam warranty, saved $$$$.

Anyhow regarding your noise, It sounds (like someone has suggested) a weight transfer occurring when the speed changes. I would suggest FIRST make sure things are secure in the basement, then get on the road and try different speeds to see if the noise increases or decreases or disappears.

If it continues, get on a creeper and take your time looking under the coach, look for anything that stands out, like a shinny spot, or where something has rubbed dirt away. Hopefully you have had the chassis lubed. Hope these suggestions help, good luck!