Mysterious Rotational Noise Under Ford E450 Chassis

Dreanmachine · 07-07-2019, 05:25 PM

Hi folks, my first time to post and looking for some level of resolution with a strange sound coming from under the Ford E450 V10 chassis/engine on my brand new Thor 2019 Quantum WS31 rig. The unit is about two months old now with about 3K miles on it. We traded in a 2018 Thor Chateau 28X with the same For E450 V10 chassis/engine and never had this behavior. Here is what we are experiencing, and I am looking for some possible reasons before I take it into a Ford mechanic. As follows:

Probably 80 percent of the time, as we start off cold with acceleration, a 'whirring' sound starts up and is tied to the rotation of something, either tires, or drive shaft, bearings, etc. I am not very car mechanical. As the RPMs increase, the noise is still there, but highly diminished and over time, it seems to go away. Then when we brake and eventually come to a stop, the whirring sound comes back. There are some times when we never hear it at all, and I think it has resolved it's self. I am concerned that there may be a safety issue, but who knows. Anybody got any thoughts on this mystery sound? Thanks in advance.

Lt Keefer · 07-07-2019, 06:11 PM

Take it to your nearest Ford dealer that handles medium duty trucks. The chassis should be under warranty.

**fhenn** · 07-07-2019, 07:41 PM

Might be the clutch Fan

Oneilkeys · 07-07-2019, 07:58 PM

It very well might be the engine cooling fan cutting in when the engine is under load going up hill or gets hot. It is a relatively loud whirring noise. But if it worries you, for your piece of mind I would make a stop at a Ford truck dealer.

Dreanmachine · 07-07-2019, 08:06 PM

I may not have characterized the type of sound very well as a few replies have come in. I apologize and let me try to further define.

The sound increases and decreases with acceleration and deceleration. When I slow down for example and the wheels slow to a stop, the sound slows down in harmony with the wheels or drive shaft slowing in rotation. And just the opposite when I accelerate. That’s why I have tried to tie the sound to something underneath that rotates faster and slower in its function. There is no fan sound present.

airforceret · 07-07-2019, 08:56 PM

Could be the center support bearing on the driveshaft.

jd hogg · 07-08-2019, 04:42 AM

I had a noise much like yours on my Four Winds Sprinter. It turn out to be main harness where it crossed over the driveshaft, the harness dropped down and was rubbing the flange on the driveshaft. found it after it started blowing fuses. I guess Thor was running short on wire ties that day. JD

The Gritz Carlton · 07-08-2019, 06:21 PM

Something rubbing somewhere or a carriage bearing. The frames are modified, which also means the drive shafts are extended as well...adding additional carriage bearing(s) if necessary. If you can elevate the rear wheels and have someone (VERY LIGHTLY) engage the driveline, you may be able to hone in on the noise by just listening from ground level. It could also be a break part rubbing on something. Usually, when the noise increases and decreases with RPM/speed as you describe...something is rubbing.

Peterrrr · 07-12-2019, 01:10 PM

This may help to solve your issue.

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**16ACE27** · 07-12-2019, 01:30 PM

Have you crawled underneath the motorhome and done a visual inspection? Could be some wires, hoses, etc that Thor didn't secure laying on your driveshaft.

Dreanmachine · 07-12-2019, 01:47 PM

I had the dealership do such a thing and they could not find anything obvious.

kwplot34 · 07-13-2019, 07:03 AM

It could be the ring and pinon gear in the rear differential, If it was not set up right it can be noisy. I have had some that were noisy and as the wear/break in the noise goes away.

GilTphoto · 07-22-2019, 05:28 PM

My 2017 Quantum WS31 started making similar noises at 20,000 miles. Haven't had it checked out yet. Will watch this thread.

Dreanmachine · 10-02-2019, 07:29 PM

To end this thread with what the solution was. It turned out to be a failing carrier bearing on the driveshaft. My local Ford repair shop replaced it for $400 under manufacture warranty. No more funky noise when accelerating and braking. Though I’d close the loop.

Lt Keefer · 10-02-2019, 07:51 PM

Please explain paying for a warranty repair.

Dreanmachine · 10-02-2019, 07:58 PM

I paid nothing. I have a third party Ford and RV repair place nearby the home. The cost was covered by my dealership and they went to fight with Thor. I was fortunate that my RV dealership was willing to work with me. For me to get in the queue for a Ford dealership that services RVs in SLC, was a handful of months. Bottom line is that the issue was a carrier bearing. That is what I want to convey to those who might be experiencing similar noise.

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