Class C Driveline Vibration

[Fish]

Hi Folks,
Have been monitoring the Forum for some time. Really good stuff. First post though. Bear with my "newbieness".

Any of you out there know of or have any experience with drive-train vibration in a Class C? Kindof a long story--so I’ll summarize. I have a Thor Four Winds 31W--2016--purchased in June of 2019 with 22,000 miles on it. In February of 2020, I took it to a local Ford dealer (their commercial truck shop) for inspection, front end alignment, steering stabilizer replacement and heavy duty sway bar installation. At the time, when they took it for a test drive, they indicated they felt a significant vibration and suggested having the drive shaft balanced. I had not really noticed the vibration previously, but then the unit was new to us and after having towed a 5th wheel with a 3500 dually for a number of years, the Class C diving experience was totally new. So, I had that work done too. They sub’d it out to a local shop that specializes in drive shaft work.

What I noticed, once I got it back, is that there still seems to be drive-train vibration that begins low cycle vibration at about 45 mph, peaks at about 55 and then starts to decrease at 65. Since there’s still warranty left, I have it back at the Ford garage for evaluation.

I’ve tried researching the Forum to see if there’s any history on this topic, but have not found anything. So I thought it was time to put the question out there to you experts to see if anyone’s been down this road before and can help me help the shop resolve this.

Thanks in advance for any insights you might have.

Dave

[Beau388]

Originally Posted by Fish

Hi Folks,
Have been monitoring the Forum for some time. Really good stuff. First post though. Bear with my "newbieness".

Any of you out there know of or have any experience with drive-train vibration in a Class C? Kindof a long story--so I’ll summarize. I have a Thor Four Winds 31W--2016--purchased in June of 2019 with 22,000 miles on it. In February of 2020, I took it to a local Ford dealer (their commercial truck shop) for inspection, front end alignment, steering stabilizer replacement and heavy duty sway bar installation. At the time, when they took it for a test drive, they indicated they felt a significant vibration and suggested having the drive shaft balanced. I had not really noticed the vibration previously, but then the unit was new to us and after having towed a 5th wheel with a 3500 dually for a number of years, the Class C diving experience was totally new. So, I had that work done too. They sub’d it out to a local shop that specializes in drive shaft work.

What I noticed, once I got it back, is that there still seems to be drive-train vibration that begins low cycle vibration at about 45 mph, peaks at about 55 and then starts to decrease at 65. Since there’s still warranty left, I have it back at the Ford garage for evaluation.

I’ve tried researching the Forum to see if there’s any history on this topic, but have not found anything. So I thought it was time to put the question out there to you experts to see if anyone’s been down this road before and can help me help the shop resolve this.

Thanks in advance for any insights you might have.

Dave

The Ford 90 degree V-10 has three vibration periods. Two are somewhat canceled by the engine's balance shafts and engine motor mounts. The third one is around 2,000 rpm and again in the 4,400 rpm range. Mine is severe enough to make the tailpipe hit the heat shield on the coach.

You could have a driveshaft that is out of balance but MorRyde usually does a good job of balancing the drive shaft before Thor MC gets the chassis. Inline 5 cylinder engines are notorious for the vibrations. So much so that they require active engine mounts. Putting two together in a 90 degree engine does not make then vibrate any less.

[Bob Denman]

I know that it's early for this type of failure... Could it be a universal joint going bad?

[Fish]

Thanks for the feedback. I had not realized there'd be an engine contribution to the vibration issue.

Universals I believe were checked when they balanced the drive shafts. I have to wonder though whether the shop got the balancing process right. I also doubt they balanced both as a system.

D.

[Bob Denman]

If they the drives haft back in place, and didn't get it indexed correctly:

[OrdpeteMH]

My 2019 E450 started with a driveline humming/grinding at 1500 miles. It went to ford and MORryde suggested a driveshaft realignment and balance. It helped quiet the noise but it was still present. Manageable, but present.

At 10000 miles, it began to get really loud again. 63-69 mph range in sixth gear, under light constant throttle, it would just sing. I mean vibrating the floor in the back.

Once again, it went back to get fixed. This time it was at MORryde's factory in Wakarusa while my Busch was getting repaired at Thor. Whatever they did made it worse.

So now it is at Gator Ford again and I was able to duplicate the problem for their technicians. They are thinking it is at least a bearing or the differential.

I took a sample of the differential gear oil before it went to ford and sent it to Blackstone labs. The fill plug is magnetic and had quite a bit of metal "fur" on it. Their report states that the oil had metal in it that is consistent with 36000 miles of wear. My coach has 12000 miles. So I'm hearing that the wear is accelerated 3 times more than it should be?

I am hoping whatever they do fixes it.

[Fish]

Well, interestingly enough, I talked to the Ford Service Advisor on Friday to get an update on their progress. They believe they've ID'd the issue--metal filings in the differential. Replacement parts are on order and I should know in a couple of weeks if this does the trick. I'm hopeful. Seems odd that this type of failure would occur relatively early.

D...

[ducksface]

I understand running over a mattress can cause a vibration.

The last drives haft I had balanced made a wonderful difference in the entire vehicle at almost any rpm. I watched him heat a little spot the size of a quarter, get it to straw colored, quench it with a wet rag, and then look for the next GRAM to work out of it.

I'm having a bit of doubt about shavings causing vibration. Vibration may have caused shavings though.
And
If it's the rear end I'd have noticed, I'm pretty sure, a difference in loaded and unloaded rear end(accelerating, decelerating, coasting) and probably a difference in making a right turn versus a left.
Or
Not.

I'd sure get a second(and then some) opinion, and/or a guaranteed in writing money back if this is just a
Parts cannon
Shot at
'we think this'
And they aren't even close to right.

I have sincere doubts about their diagnosis.
Lots of rear end things can do this, pinion wise.
Shavings are a sign, not a cause.

As said above, by Beau who has a HUGE knowledge base:
It might just be the harmonics of it all, and I'll add to his perfect reasoning: the people telling you of it has triggered your awareness.
I'd sure bet on that.

Aside :
My 70 1/2 z28 LT1 350 hit resonance and was VERY noticeable. Solid motor and trans Mounts made the whole car kinda have a not so subliminal hula roll to it. It happened at I think 2150 rpm... At exactly 55mph back in 55 mph days.

This is for sure one of those:
Until it's bad enough, or your mechanics diagnosis skills are good enough, leave it alone until it can DEFINITELY be diagnosed.

A differential is not a thing you want a dealership
Read, remove, replace type mechanic touching.
He changed a headlight yesterday and will work on your rear end tomorrow.

Go to an offroad shop and have them look at it.
A dealership will change 3 diffs a year on the far outside guess and maybe only 1 in 3 years, but an offroad shop does 5 drive lines a week.
As said above, a dealer can sure make it worse.
Jack of all master of none, or a specialist.
Choose the specialist.
Your differential, once out of warranty, should have nothing ever ever to do with a Ford dealership mechanic.

[Bobo]

I had a 1999 Tioga class C that broke a belt on one tire on the way to Fl. It started with a little vibration that increased over a few states. Eventually, the tire bounce melted the seals on the shock and released a spray of oil onto the brake rotor causing an exquisite cloud of smoke to blossom out! Changed the shock in the AutoZone parking lot, (New Years Day) then changed the tire (of course the spare was nearly flat). Got to FL. and replaced all of the tires... Good times...

[BASSMAN]

in the old days we would put a hose clamp on the drive shaft and move it after each test drive to see if it made it worse or better, the weight of the screw part of the hose clamp is enough to cause or eliminate a vibration, another problem is having a drive shaft out of phase, this happens when some one has the drive shaft out and removes the slip joint from the drive shaft and reinstalls it and does not line up the yokes of the drive shaft with the yokes of the slip shafts, when the flats of the yoke are up an and horizontal at the output of the transmission all the flats on all the yokes should line up all the way to the differential, one other problem is the drive line angle at the differential, unless the rear axle housing or leaf springs have been changed and some one left out a wedge between the housing and the leaf spring you should not have a problem with that, usually wedges are added when problems start and sometimes make problems go away or make them worse, fuzz on oil plug is normal, its a problem when you have chunks, pull the rear cover off the axle housing and inspect the gears, or have a shop do it if you are not comfortable with a DYI, I chased a vibration noise on a coach years ago and it ended up being the license plate frame on the front bumper, they only had two top screws in it and I added two more to the bottom and problem went away, I had walked past the front bumper and my pant leg caught the frame and it made the noise I was hearing, drove me nuts for a wile

[OldWEB]

Driveshaft phasing was also my 1st thought after bad u-joints. Here is a diagram of what is happening. With a slip joint driveshaft, it could be out only a few degrees and cause problems. Something simple to check (and also miss). Good luck!

[ajordan282]

What came of this? I am going thru the same thing. Would much appreciate some help.

[OrdpeteMH]

Ford dealer replaced my differential bearings and it is now silent. All is good.

[Fish]

Vibration in my Thor Four Winds 31W drivetrain turned out to be the front carrier bearing. The local Ford Commercial Truck center worked with Morryde (who does the chassis extension) to confirm angles were correct. Ford had the drive shaft balance and universals checked. They were ok. Tech could feel the vibration over the front carrier bearing so they ordered one from Morryde and that seemed to cure the majority of it. That's all I paid for. Ford warranteed the drive shaft check. I still feel a very, very minor vib going thru 60 mph, but it's not worth the effort to trouble-shoot it at this point. I like hanging out at 55 anyway. ;-)

[ajordan282]

Thanks OrdpeteMH and Fish. I am thinking its a differential carrier bearing at this point but going to replace the driveshaft carrier bearing first since its easy. rv is still under warranty but all the dealerships around me are booked for the next 2 weeks.

I also ended up reaching out to rv MFG and they sent me a sheet to fill out with my driveshaft angles, waiting to hear back from them but I'm guessing they're going to say thats not the problem.

worst case i may crack the diff open myself and replace the diff carrier bearings. im getting impatient.

from what I understand, the pinion bearing would make more sound when im on the gas vs. off but this is constant so im ruling that one out. and the axle carrier bearings would change the sound when i steer at 70mph (as you load up one more than the other) but that is not the case either. this is why i am thinking diff carrier bearings.

[Sappy2]

This is written to address E350 - but much of the principles are the same. It is all about balance, run out, drive line angle and any issues with cross and roller as well as center bearing mounts. Tires can also be felt as driveline at times. As the RV ages, so does its springs and drive line angle. All of this can be determined by a tech that knows how to measure and assess the entire system.

QVM Bulletin No. Q-45 Date: October 18, 1996 Retain This Bulletin in Your Technical Bulletins Binder for Future Reference DRIVELINE VIBRATION ISSUES WITH THE E-350 CUTAWAY AND E-SUPER DUTY Please share this information with engineering, manufacturing, dealers, and service departments. Questions have been raised concerning driveline vibrations in completed vehicles incorporating Econoline Cutaway vehicles and in Econoline Cutaway incomplete vehicles. Incomplete Econoline Cutaway Vehicles (as received from the Ford plant) The driveline angles for the Econoline Cutaways are designed to be optimum when the completed vehicle is loaded near the Gross Vehicle Weight Rating (GVWR). When the cutaway chassis is unloaded (“bare”), the driveline angles are not optimized and some objectionable driveline vibration can be expected. This is especially true with the E-Super Duty chassis. Therefore, do not attempt to eliminate driveline vibrations noticed on a “bare” Econoline Cutaway chassis unless there are loose driveline components or there is visual damage to the driveline. If the chassis driveline is to be modified during the vehicle build process, refer to Bulletins Q-14, Q-18 and Q-40. Completed Vehicles having Modified Drivelines QVM Bulletins Q-14, Q-18 and Q-40 describe methods to modify (“stretch” or “shrink”) the Econoline Cutaway chassis wheelbase and give guidelines for modifying drivelines. Because of the many different configurations of completed vehicles, these Bulletins can only be considered guidelines and the builder has the final responsibility for the modified driveline design. Field investigations of many driveline vibration issues shows that driveline balance and runout specifications stated in Q-14 are often not being met and that some driveline angles do not meet Q-14/Q-40 guidelines. Assistance in driveline design and obtaining components that meet these requirements can be obtained from Dana-Spicer

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