Minnie Winnie Noise Decelerating with engine brake

[SR2022]

I bought a 2022 MW26T from an RV show in Feb 2022. First Winnebago product. I'm overall happy but there were many ticky tacky items I had to fix or tune up. Quality of workmanship is fair.

I have one concern with the 7.3 V8 that I'd love to get other owners to chime in on: when decelerating using the engine brake, between 3000 and 3500 rpm (decending a steep grade...) I get a pretty loud rattling sound, almost like a leaking manifold. I've searched for loose exhaust shields and found nothing. No "ticking" during idle. Just when decelerating at that rpm range. If you tap the throttle the rattle goes away.

Anyone else notice this? Could be normal?


Tried to record the spund using my phone but I cant get a good quality recording. Reluctant to take it to the ford dealer for an inspection. Just generally don't like other people working on my rigs.

[Raxel7851]

Originally Posted by SR2022

I bought a 2022 MW26T from an RV show in Feb 2022. First Winnebago product. I'm overall happy but there were many ticky tacky items I had to fix or tune up. Quality of workmanship is fair.

I have one concern with the 7.3 V8 that I'd love to get other owners to chime in on: when decelerating using the engine brake, between 3000 and 3500 rpm (decending a steep grade...) I get a pretty loud rattling sound, almost like a leaking manifold. I've searched for loose exhaust shields and found nothing. No "ticking" during idle. Just when decelerating at that rpm range. If you tap the throttle the rattle goes away.

Anyone else notice this? Could be normal?


Tried to record the spund using my phone but I cant get a good quality recording. Reluctant to take it to the ford dealer for an inspection. Just generally don't like other people working on my rigs.

We’ve noticed that with our 2021 22M on the E-350 chassis. We didn’t notice it our first year of owning it, but on the 2nd year we heard it on a 2,200 mile trip to Florida. It seems to be something “harmonic” because as you noted it only does it when de-celerating. We thought it could be a heat shield loose. At idle the engine is super quiet though. We just turned 6,800 miles.

[SR2022]

Thanks for responding. I have about 7000 miles on the odo. I'm leaning towards "keep going till it fails" but would hate to have it fail when I'm in the middle of nowhere between destinations (Murphy's Law).

I wonder how the engine break in procedure could have influenced this. Ford suggests varying throttle and load through the first several hundred miles (typical ICE break in procedure) most Winnebagos leave IL with hundreds of miles of flat highway which is exactly the wrong way to break in a new engine.

At least the power train warranty is through ford.

Another note: seems louder coming from the passenger side.

What I would really love to do is take an E450 cab and chassis for a test drive and see if I get the same noise.

Let us know if you end up taking yours in for a diag

[Raxel7851]

Well guess what? Ours is on the passenger side as well!!!

[SR2022]

Originally Posted by Raxel7851

Well guess what? Ours is on the passenger side as well!!!

Yeah I'm gonna say not a coincidence. I'll be doing a spring cleaning on the 26T in the next week or so. Will do a deep dive on the passenger side exhaust manifold, downpipe, shields etc.

Hard to diagnose because of the circumstances necessary to create the noise. Tried to do a slow rev to 3000 rpm but seems the engine rpm is limited while in P and won't climb that high 🤔

Will report back after my inspection In a week or so.

Will say this though, love the engine power characteristics. She handles the weight of the RV with no problems. I pull a 3000lb v nose trailer from time to time and don't even notice it back there. Avg mpg 9.5 to 10 burning 89oct through rolling hills on the hwy

[SR2022]

So just went through the engine bay from above and below and found nothing loose and nothing amiss. So the sound remains a mystery.

I did run in to a guy with an E450 with a work box on the back and asked him if he ever uses the tow/haul to control his deceleration. He said he uses it all the time and it doesn't sound pretty when he's descending a steep grade. I couldn't get more specifics on the sound or perceived location from him, wasn't very chatty.

Guess I'll just run it, enjoy it, and worry about it when it's something to worry about.

Happy Rv'ing