Seneca Cab Noise at Highway Speeds

[byrdbody]

This is how I fixed all the noise, like driving a different vehicle now. J Byrd

[jsimonson]

What is the composition of the boot?

[byrdbody]

Kind of a foam rubber about 3/16" thick. It was from a sort of an exercising mat I had bought to line the inside of some fiberglass fender I had on a hotrod truck of mine. I cut it in kind of a rounded edge triangle shape then strapped it down with a couple black nylon tie straps. Worked great, every time I see someone with one of these rigs I show it to them. Are you having any problem with your fresh water tank bulging underneath? J Byrd.

[dhauser]

After much testing I found the exact locking hole plugs to fix the Freightliner M2 issue.

https://www.jaycoowners.com/forums/f...tml#post569937

[RVr2]

The whistle is gone! Thank you one and all for your analysis. It was spot on. We wrapped the outside mirror holes with electrical tape. Bingo - all is quiet in the cab. Will order some locking caps now for a more elegant solution.

[RayBo]

My 2012 is noisy as well. None of the 'fixes' has worked. Mirrors, holes, etc, were not our problem.

What I've discovered is that the profile of my driver's door does not match the profile of the cab. Therefore, the top of the door "scoops" air which passes the gasket and creates noise.

I verified this by putting a thin strap around the door frame, with a regular ratchet strap that I attached to the passenger seat frame.

One or two clicks of the ratchet to close the gap and the noise went away.

Not sure the final solution, but I need to bend the door to make it match the opening, which I think I can do. (We make things out of metal here.)

I'll post later if it makes sense. Anyone with any advice, please say so.

[RichP]

Originally Posted by RayBo

My 2012 is noisy as well. None of the 'fixes' has worked. Mirrors, holes, etc, were not our problem.

What I've discovered is that the profile of my driver's door does not match the profile of the cab. Therefore, the top of the door "scoops" air which passes the gasket and creates noise.

I verified this by putting a thin strap around the door frame, with a regular ratchet strap that I attached to the passenger seat frame.

One or two clicks of the ratchet to close the gap and the noise went away.

Not sure the final solution, but I need to bend the door to make it match the opening, which I think I can do. (We make things out of metal here.)


I'll post later if it makes sense. Anyone with any advice, please say so.

You most likely need to just adjust the door hinges. They have a lot of movement you can play with. If you aren't comfortable doing it, any truck shop can do it relatively inexpensive

[Lolead]

Ray, If yours is a Chevy cab I believe there will be no adjustment in the hinges, pickups a, at least, are welded hinge assembaly. Bending the door frame is not difficult as I have done this many times in the body shop for nearly 40 years. Open the dorr, roll down rhw glass, put your knee against the inner door trim panel and grab the door at the upper front corner.Then firmly give a couple of tugs. Don't try to spring it all at once, it is easier to spring it in than it is to ty to unkink it . Good luck.

[RayBo]

Originally Posted by RichP

You most likely need to just adjust the door hinges. They have a lot of movement you can play with. If you aren't comfortable doing it, any truck shop can do it relatively inexpensive

Thanks to everyone for suggestions.

It's a Freightliner, and if you consider the door in three dimensions, the error is not in the X-axis, which might be adjustable with the hinges, rather my problem is in the Y-axis, particularly when measuring the difference between the -Z and the +Z. It's as if the door frame, near the top (+Z) is bent away from the cab just a bit.

I've also looked at the hinges which are aligned properly. With a plumb bob and by measuring the angle of the door in relation to the angle of the cab, the door is about 1.5˚more "vertical" than the truck frame. It's never been crashed. The gap on the driver's side is about 5mm more than on the passenger side at the +Z (near the top of the window.)

Soon as I pulled it in with the ratchet strap, the noise resolved.

I'm going to dig further and welcome any comments or ideas. I'll post the solution once I find it.

[CM2678]

This is a loud whistling sound that happens mostly while coasting at 60 or above. If i place my hand over the shifter mount it becomed muffled.

[RayBo]

Originally Posted by CM2678

This is a loud whistling sound that happens mostly while coasting at 60 or above. If i place my hand over the shifter mount it becomed muffled.

There is a Freightliner recall that replaces a mounting bracket to your transmission cable. This eliminates the noise. Jayco won't/can't help you, but any Freightliner dealer will handle it for free under warranty. Mine was really bad and after the replacement, it's now silent.


Good luck.

[Rustynuts]

On my 2018.5 plugging the mirror hole helped a lot but I finally just adjusted the doors a you could slide a piece of paper in both upper front corners of the doors. This took about 10 minutes and made a big difference. Here is the instructions out of the service manual if anybody wants to do it themselves.

[jsimonson]

If the whining also has a rattle most prevalent between 55-65 mph this is a transmission issue. Took mine to Freightliner while still under warranty there is a fix by putting rubber grommets in the shifter plate in the transmission isolating the noise. I really do not see this as a “fix” yet their version of a fix. The service center in Fontana, CA said they had seen a dozen of this issue in RV’s as they thought Allison needs to address this issue not a problem in other transmissions just this one.

[21stcenturymusclecar]

Originally Posted by memphis02

One other thing you might check is the Shifter Cable. If it's happening once you get into top gear at highway cruising speed and goes away immediately after you let off the throttle, that might be your issue. Some have described it, almost as a high-pitched cricket noise or something similar. For me, it was positively deafening. I took mine to FreightLiner over the issue and it was addressed under TSB-355625 / KPP-294201 and isolator kit 2650 fixed the issue. The kit was only $100 but they took 2 hours to install it so it ended up being about a $300+ fix. -It did solve my particular issue, however and was well worth it.

Can anyone give me more help on this please, I have the same irritating noise
I have called Freightliner parts and service with these TSB and part #s
I was told to call Allison, so I talked to Allison both parts and service and finally talked to Jayco parts and service and NO ONE knew what I was talking about or have heard of the problem.


Anyone?

Thank You in advance,
JP

[Rustynuts]

Originally Posted by 21stcenturymusclecar

Can anyone give me more help on this please, I have the same irritating noise
I have called Freightliner parts and service with these TSB and part #s
I was told to call Allison, so I talked to Allison both parts and service and finally talked to Jayco parts and service and NO ONE knew what I was talking about or have heard of the problem.


Anyone?

Thank You in advance,
JP

What year is your Seneca?

[21stcenturymusclecar]

2012

[memphis02]

Originally Posted by 21stcenturymusclecar

Can anyone give me more help on this please, I have the same irritating noise
I have called Freightliner parts and service with these TSB and part #s
I was told to call Allison, so I talked to Allison both parts and service and finally talked to Jayco parts and service and NO ONE knew what I was talking about or have heard of the problem.


Anyone?

Thank You in advance,
JP

I wonder why they weren't able to pull up this fix directly from those numbers???

You might try to contact Truck Centers, Inc in Mt. Vernon, IL (618) 244-2545. I would call between 7am and 3pm CST and ask to speak directly to the technician that handles RVs. They were the ones who did my work and solved it on the first try.

[21stcenturymusclecar]

Awesome, Thanks!

JP

[21stcenturymusclecar]

Was that the correct part in the Ebay link?

Could you please post that back, I can do the work

Thanks,
JP

[Robbbyr]

Shifter noise document, might help.