Drive line vibration diagnosis

OK, it's taken a while to get my 58-62mph vibration issue diagnosed.  To recap:  The first try was to get all 6 tires balanced.  The improvement was slim although the tire company told me all 6 tires were out of balance (cost $15/tire)  I took it back to the tire company to see if this was the best they could do and took a run with a mechanic.  He diagnosed it as a suspected driveline issue not the tires.  The recommendation was to take it to Ford and try to get it fixed under warranty.  If that didn't work, bring it back and they would locate the vibration with a sensor machine. 

I finally got it into the Ford dealership and they drove it and rebalanced and indexed the tires and told me it was fixed (cost $0).  I picked it up and drove it to the nearest highway and it rode smoother due to a little better balance job, but the vibration was still there.  I drove back to the Ford dealership and complained and a service manager agreed to take a ride with me.  Once I got the PC up to 60 mph, he heard/felt the vibration right away and he tried to locate it.  He said it was worse behind the transmission.  He asked me to leave it until he could look at it on a rack.  They only have one truck rack and it was in use so it sat a few days. 

Today he called and said it was as fixed as good as he could get it.  The problem, according to him, is the driveline is not straight because the factory added coupler is off center by 1/2".  The added coupler is about 1/2" off center towards the passenger side and this is causing my problem.   I asked if he could just slide the coupler 1/2" towards the center of the vehicle and he said, no, the adjustment on this particular bracket is fore and aft, not sideways.  I asked if he could grind the bracket holes out so the coupler could be slid to the center and he said no, there is only about 3/8" of metal on the edge of the existing hole and there is no room to grind.  He thinks the only way to fix it properly is to cut the welded bracket off and then weld it back in the right place.

He attempted to fix the problem by shimming the coupler down.  He tried 5 shims and it got best at 3 shims and then got much worse by 5 shims.  He went back to 3 shims.  He thinks it's about 50% better (Cost $0, thank you very, very much).

He also said an out of line driveline is consistent with the vibration ramping up and then ramping down as speed increases.  If the shaft was out of balance, he said it would ramp up and up and keep getting worse as speed increased.

He doesn't have the equipment to fix it and recommended I take back to the factory if I can't live with it.  Since I bought it used, I don't have a warranty and it's a 2500 mile roundtrip so that solution is out of the question.  His second recommendation was to take it to someplace like camper's world and see if they could tackle it.   He is going to send me pictures and if it shows the problem, I'll post them up here.  I'll also contact Earl and see if he has any pearls of wisdom.  Mark

Here are the pictures the service manager sent me looking fore and aft.  There does appear to be a definite cast to starboard.


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Mark,

Sound like you are on the right track in getting to the root of the problem.  Some time ago I ran across a Ford bulletin regarding driveline angles in modified Econoline cutaways used for RVs.  It describes the problems that can be associated with improper driveline angles and the solutions.  It is very technical but may be of some use as you go forward to try and resolve the issue.

https://www.fleet.ford.com/truckbbas/non-html/Q40.PDF

Bob

Good Post,,,   couple questions,,,,  the bracket that is off 1/2 inch, you say factory    ford or PC?  I always assumed that PC took the 450, cut off the van body, except the front, added brackets for support items, genie, tanks, etc, and added to the frame to  lengthen if needed... Do they actually move the bracket holding the drive shaft?  I can not imagine why PC would move this,,, seems to me this is a Ford problem.

  Second,,, since the shaft is not perfect, are you risking some type of drive shaft failure in one of the joints since you are putting stress on them?  Even though you do not hear the vibration at lower speed, still stressing the shaft, brackets, joints etc I drive that speed 58to62 and know it would bother me,,,
good luck
sparky

Sparky,
PC outsources the bodies to be lengthened or at least I think they do.  When this body was lengthened a 4' driveshaft extension was added and a coupler was added to support the new shaft.  As you can see in the first picture, it appears the new bracket was welded in off center.  This bracket was added aftermarket so it's not a Ford problem.  There might be something I and the service manager may not know.  I sent an email to Earl and he has forwarded it to Kermit.  Let's see if this was intentional or a mistake.  Mark

This might be the cause of our vibration issue also so I am glued to this topic. I'm not sure I can get a decent picture underneath to see if we have the same angle. I, too, thought Phoenix sent the chassis out to be extended but then Earl's walk through video seemed to say they do it themselves. I watched them putting the heat shield on during our factory tour but I did not see if they did or did not do the chassis extension themselves. Skipper, thanks for the excellent post.

His second recommendation was to take it to someplace like camper's world and see if they could tackle it.   He is going to send me pictures and if it shows the problem, I'll post them up here.  I'll also contact Earl and see if he has any pearls of wisdom.  Mark

I don't believe I would ever take a problem like this to Camping World. Lippert Industries in Elkhart does the chassis modifications for PC. They might work on it. Good luck!

John, the vibration I am experiencing starts at about 58 and is worse at 60 to 62 and then it subsides by 65 mph.  I can both hear it and feel it.  I spoke with the previous owner and he never mentioned the vibration, so either it didn't bother him, he thought it was normal, or he never drove at these speeds.   

The service manager said this vibration was consistent with an out of line driveline (ramp up and then down).  He also said if the vibration starts and got worse as speed increased and never got better, it was most likely an out of balance driveline.  He said you can often see an out of balance driveline if you put the truck on a rack and lift the tires and run it.  You can see an obvious flutter. 

I traded emails with Kermit and I'm awaiting his response as to whether he disagrees with the service manager's assessment (maybe all PC's drivelines are off center for a reason) or if he agrees.  If he agrees, then what is the best fix? Mark

Joni and I will be taking delivery of our 2552 at the end of next week, and amongst the list of things we will be having our RV techs and Ford techs take a look at is this driveline issue.  We will surely post what we find. Will be nice to contribute for a change!

Very interesting info....   I am also learning..... I did some research trying to look at different wheelbases in the 350/450's   I'm also surprised that these  frames are done like that,,  your never too old to learn...   I also realize they have been doing this procedure for years and know what they are doing.... How ever I don't have to be an engineer to know that if you cut a 10ft piece of steel in half add two feet in the middle you are going to get differences in the flex,vibration,etc,,,, and when you take two  pieces that are connected to each other into a square and add two feet the same thing is going to happen,, I would love to see them do this procedure simply amazing to me..  
     I would assume when ford builds theses frames, they have a set up where when they do all this (putting the frame, cross members together) that the specs are very tight...  Now you take a squared factory frame cut it in half, add new cross member, add extensions to drive shaft and other stuff, it is amazing to me...  wonder how much square is off,,, wonder if this could be a major issue in alignment in our units or could it just be the weight,,, anyway very interesting
   Hopefully you guys will get an answer and be able to solve the problem,,,, still would like to know if this could result in drive shaft failure since there is more stress on the u joints, brackets from excessive vibration  
sparky

I wonder how many class C and class B+ that use a wheel base greater than 158 inches? Thinking about how many have been made in the last 30 years? Now I would think every now and then one might be welded incorrectly but that most of them would be corect. I would not worry about them adding the extended frame to the orignal fame. Life is too short to worry about everything.

Good point Tom... I'm just a curious (noisy) person haha,,, I think I understand they have been doing this a long time and matter of fact I think it is really neat,, but I would not want to be one of the guys stuck with a problem and no matter what when you do this 100's and 1000's of times boo boos happen,,,
sparky

I agree that the industry has nailed down the frame extension process so I would get whatever floor plan I wanted, stretched frame or not.

But still there is a little peace of mind that our 2350 has an unmodified 158" wheel base.  It's nice to know that all parts are stock/generic.  For example, if I needed a parking brake cable, a brake line, a fuel line, drive shaft, whatever, on a trip, I know the shop in No-Where USA can get a Ford stock part right away, rather than fabricating something to get me back on the road.

You are right about having all standard parts is nice, but how often do you have a problem with thses parts? If I have a problem with any of my parts, I will call Carol at the factory and ask her to overnight them. No worries here.

Warning:  long post.  Read last paragraph if you are in a hurry.

Captain's log:  Stardate 10/22/13.  Work continues on fixing the vibration.  I drove the RV home after the Ford dealership diagnosed an out of line drive system and they attempted a repair by shimming the 2nd coupler 3 shims towards the ground.  I couldn't feel any improvement, but wasn't any worse.

I contacted Earl and sent him the thoughts of the Ford folks and pictures of the driveline taken by the Ford service manager.  Earl replied stating he forwarded my email to Kermit.  Kermit emailed me a couple of days later and said he couldn't find me in the warranty system.  I emailed back and said I wasn't filing a warranty claim and it was known to me before I purchased the rv that the warranty didn't transfer.  I was simply looking for information on whether the Ford service manager was right and how to fix my rv. 

Kermit called me 2 days later and said he disagreed with the service manager.  The driveline is offset by design towards the passenger side because the engine is offset towards the passenger side and so is the rear axle.  Kermit thought the problem was likely an unbalanced driveshaft and he suspected the rear driveshaft because that is where he had experienced problems in the past.  According to Kermit, before the chassis is extended, the driveshaft may not be "in spec" but it's not a problem until the chassis is extended.  Once extended, little problems are magnified.  He said the company doing the extension has years of experience and has their part of the extension perfected.  They rarely make mistakes.  The extender uses the Ford driveshafts and add one for the length of the extended chassis.  He recommended finding a driveline balancing company and see if they could find the problem and suggest they start with the rear shaft.

I located a driveline balancing company in the next town and took the rv to him yesterday.  The owner's credentials are 17 yrs of driveline experience working for Ford dealerships in the area.  He claims to be a Ford's master driveline technician, the highest level that Ford certifies.  He seems to know his stuff.  He hooked up his analysis equipment and found a driveshaft vibration.  However, he doesn't know which shaft is out of balance.  The shaft coming out of the tranny is an aftermarket shaft and the rest of the line is Ford (actually Spicer, a supplier to Ford). 

He asked if it was possible the driveline was under warranty by PC or Ford.  I know PC won't cover it, but I called the Ford guy and asked him.  His response was maybe.  His concern about a warranty claim was Ford would want to know if the driveline was balanced as a whole or by its individual parts and was the extender certified by Ford to be covered under the Ford family umbrella.   The deal about balancing by part is that Ford balances the entire unit and the splines must match exactly or you can get an out of balance driveline.  Care must be taken to line everything up just the way Ford tested it or Ford wouldn't warrant it.  And even if it is out of balance, Ford may balk paying a claim anyway if the extender isn't certified, Ford doesn't pull the shaft out and verify it, blah blah blah.  He said he sees a lot of finger pointing between Ford and RV manufacturers and the customer is usually the one that ends up paying.  This is the fourth time I've had it in a shop for fixing and I'm growing weary.  So I called the driveline guy back and said just fix it. 

I asked him how he was going to approach balancing the system.  This is my understanding:  He will pull the 3 section shaft and spin each part and correct any balance issue with the 3 shafts.  Then he will connect the first two and balance them together (messing with spline alignment) and get it as good as he can noting any 'high' spot.  Then he will do the same on the rear two noting any 'low' spot.  Finally he will put it back together with the high spot on the 1 and 2 matching the low spot on 2 and 3.  Then he will test drive it and it should be fixed.  I can only hope!  Sorry for the very long post.  Mark