This is a copy of a post I placed on tiffinrvnetwork.com. The chassis for the 35QBA is a 24,000LB F550. Posting here to see if any Ford enthusiasts can help identify the noise we are experiencing.

We bought a 2013 35QBA in January of this year. During the first three months of owning the rig we noticed a high pitched noise coming from the engine compartment/dashboard area. This only seemed to happen when we had the 16' utility trailer with our dirt toys in tow. We took it to our local Ford dealer, told them about the noise, and left it for a week with them. They reported back that they were unable to reproduce the noise and let them know if it happens again.

Since then we have had that same noise towing up hill......going down hill when the transmission down shifts, and sometimes just while driving mostly flat roads with some rolling hills (think Oklahoma and Texas flat). It also appears to happen more frequently when it is warmer outside ( above 88-90 or so). We have been on our summer vacation in the RV for the past 7 weeks and have been dealing with the noise the entire trip. We took it to a Ford dealer in Branson MO because we had a time share to stay at for that week. We took the tech for a ride with the trailer attached and he was able to hear the noise....unfortunately he was not able to find the issue nor reproduce when the trailer was not attached.

Since we have tried twice at Ford I thought I would post this question along with a link to a YouTube video of the noise as it happens. The noise in this video is the high end of the spectrum...there is a quieter version of the noise that also occurs on a regular basis but is very hard to hear over the engine noise. To see / hear the video click below.


During this video you can see that the RPMS are around 4K and we are doing ~70. This same noise can happen at 2.5K RPMS and 50 MPH....extremely variable and frustrating.

We have weighed and the trailer with toys comes in around 3500-3700 pounds depending on the combination of toys on the trailer and the real axle runs right at maximum load. Typically we usually carry about 1/3 tank fresh with us at all times.

Any insights would be appreciated as this is becoming very annoying to deal with on a daily basis while we are on the road.

Thanks,
Joe

 

Wow, that's a new one...

First, I'd go back to the (or any) dealer with that video and let them know exactly what it sounds like.

Could be intake noise, could be just about anything. It's more of a whistle than a squeal, yes?

 

Thank you for posting this, we have the same problem our RV is in for repair and they have not heard of the problem. We're you able to figure out what the problem is, and did they fix it? Your reply will be greatly appreciated

 

I also have a 2013 tiffin motorhome and its at the dealer for the same problem. They have no idea what it is. I will post if they can find anything.

 

My guess is a vacuum leak, either from the intake manifold or a hose. That being said, vacuum would be less under heavy acceleration, so not sure why that would pop up then. What about spark-arching to ground from a bad coil pack(s)?

 

Did you ever figure out what this noise was? We have the same problem now. Thanks!

This is a copy of a post I placed on tiffinrvnetwork.com. The chassis for the 35QBA is a 24,000LB F550. Posting here to see if any Ford enthusiasts can help identify the noise we are experiencing.

We bought a 2013 35QBA in January of this year. During the first three months of owning the rig we noticed a high pitched noise coming from the engine compartment/dashboard area. This only seemed to happen when we had the 16' utility trailer with our dirt toys in tow. We took it to our local Ford dealer, told them about the noise, and left it for a week with them. They reported back that they were unable to reproduce the noise and let them know if it happens again.

Since then we have had that same noise towing up hill......going down hill when the transmission down shifts, and sometimes just while driving mostly flat roads with some rolling hills (think Oklahoma and Texas flat). It also appears to happen more frequently when it is warmer outside ( above 88-90 or so). We have been on our summer vacation in the RV for the past 7 weeks and have been dealing with the noise the entire trip. We took it to a Ford dealer in Branson MO because we had a time share to stay at for that week. We took the tech for a ride with the trailer attached and he was able to hear the noise....unfortunately he was not able to find the issue nor reproduce when the trailer was not attached.

Since we have tried twice at Ford I thought I would post this question along with a link to a YouTube video of the noise as it happens. The noise in this video is the high end of the spectrum...there is a quieter version of the noise that also occurs on a regular basis but is very hard to hear over the engine noise. To see / hear the video click below.


During this video you can see that the RPMS are around 4K and we are doing ~70. This same noise can happen at 2.5K RPMS and 50 MPH....extremely variable and frustrating.

We have weighed and the trailer with toys comes in around 3500-3700 pounds depending on the combination of toys on the trailer and the real axle runs right at maximum load. Typically we usually carry about 1/3 tank fresh with us at all times.

Any insights would be appreciated as this is becoming very annoying to deal with on a daily basis while we are on the road.

Thanks,
Joe[/QUOTE]

 

Wow, that's weird. Have you tried turning off the AC/Climate-control stuff when it does this?

It almost sounds like a vacuum actuator leaking. Do you have climate-control?

 

Is that a bearing squeal in the accessory drive?

 

Hmm... could be... AC compressor clutch bearing? Which brings me back to the climate control. Does turning on and off the AC change the squeel?

 

I'm on the road again today and am going to try to replicate the noise with the A/C off.

 

I know this an old post but my motorhome has the same issue, same conditions as this. My AC goes into default and the air is routed to defrost mode until the RPM's come down. What was the outcome? I have an E450 with the V-10.

 

We never figured it out - it is very hard to replicate and troubleshoot. It does happen when the AC is off. Let me know if you figure it out!