Driveline vibration after center bearing replacement

My 2008 Sprinter 3500 was purchased new in 2010 as an Airstream Interstate and currently has almost 28K miles on the ODO. About 3K miles ago, I noticed what can best be described as a tinny squeak/scritch kind of sound. It reminded me of a small stone stuck in a brake caliper shield. It was highly intermittent; I could drive for days and hundreds of miles without hearing the noise at all. Then it would come back. To shorten a long story, it turned out to be what first came to my mind when I initially heard the noise; a failing drive shaft center support bearing. The seals in both bearings were rotating within the housing and one of them was causing the squeak.

A couple of days and about 1K miles ago, I had both center support bearings replaced by a MB Sprinter shop in Santa Rosa, CA. They also performed my first B service and replaced my windshield. Everything about this shop impressed me; they really seemed to have their act together on the Sprinter service side of the business. They even gave me a free loaner for the 2 days they had my van; a low-mileage C350.

The tech completed the road test and proclaimed everything OK and handed over the van. Shortly after getting back on the highway I thought I noticed a “new” vibration but the pavement was pretty rough in the area so I didn’t think much about it initially. Once I got to some nice smooth pavement, it became clear that something was different.

The vibration is:
• Based on frequency more suggestive of drive shaft rotation than wheel rotation
• Quite subtle, never harsh at any speed
• Always present at speeds above 30 mph
• Most noticeable at about 55 mph
• Much less noticeable at 65-70 mph
• Not felt as steering wheel wobble
• Felt mainly in the seat of the pants

My conclusion was that the driveline work had introduced the issue so I contacted the shop that did the work. After some checking the service advisor got back to me and confirmed that the tech had followed their common practice and marked all parts before disassembly so everything could be reinstalled as it was before. He claimed that they had done many of these repairs and only had vibration issues in one case. With that one they rotate the drive line 180 deg. and the problem was resolved. I expressed my concern about driving the vehicle and the advisor said it should be fine for moderate speeds and limited miles. A subsequent conversation with the knowledgeable folks at Upscale Auto/The Sprinter Store supported this view of things.

So here I am about 1K miles from the dealer that did the work; I find myself wondering:
•What is the best way to solve this problem? Let’s assume that the shaft was in fact reinstalled the same way it came out. To find the vibration-free orientation of all parts of a 3-piece driveline by trial and error could take a lot of tries. And then you would have it to a point where it SEEMED to be good. So should I push for a full dynamic balance of the entire shaft?

•Should I drive the van the 1K miles back to the dealer that did the work? They have said that is their preferred approach. They also said if I took it to another dealer it should be and warranty repair and if there were $$ involved they would reimburse me.

•By driving the van as is, is this vibration possibly causing reduced lifetime of the new bearings or other driveline components?

So, what do you Sprinter wizards think?

Oh, I’m happy to report the good news from this experience:
•As I mentioned the folks at MB Santa Rosa seem to be great, at least on the Sprinter service side. They have 4 Sprinter capable lifts and 4 fully trained techs.
•For the windshield I elected to go with aftermarket glass (by PPG) rather than OEM glass at twice the cost. And it ended up costing $60 less than the estimate. Other than the markings in the lower corner, I can’t tell the difference. And the installer did a perfect job from what I can see.
•Both support bearings were replaced with the newer (improved?) versions. The work would have cost about $1K but was fully covered under the ELW I purchased last year.
•The C350 is a nice car! I just wish they had been able to loan me the SL65 AMG I requested

Well Wayne here are some comments which may or may not be relevant to your situation.

1) Have the props been installed so that the U/J yolks are in alignment!
You can do this yourself by eyeballing it under the vehicle.

2) Sometimes overlooked in service is that the U/J units might be brinnelled or have tight spots.
The reason is that the shaft prior to disturbance articulated through a fixed arc. Now with a new centre bearing the prop has a new centre line and the natural arc is affected where the U/J spider journals now roll over the tight spot(s)--hence vibration!

3) Equally the centre bearing assy sits under a X member held in place by two bolts. There is lateral play allowed to allow the shaft to run directly to the rear axle in a lateral sense.
I use a string to "string line" the alignment so that it doesn't have and additional angular "side jog" to articulate through. This can cause additional vibration.

4) The "vibros" might have been there all along 'cept you didn't notice it!
In cases like yours I road test the rig PRIOR to dis assembly and note the vibro retorts; then I have a set of chassis ears from Snappy to "listen" to the creaks and groans of the frame when under way and driving long at the speeds making all the noises.
Dennis

lindenengineering said:

Well Wayne here are some comments which may or may not be relevant to your situation.

1) Have the props been installed so that the U/J yolks are in alignment!
You can do this yourself by eyeballing it under the vehicle.

2) Sometimes overlooked in service is that the U/J units might be brinnelled or have tight spots.
The reason is that the shaft prior to disturbance articulated through a fixed arc. Now with a new centre bearing the prop has a new centre line and the natural arc is affected where the U/J spider journals now roll over the tight spot(s)--hence vibration!

3) Equally the centre bearing assy sits under a X member held in place by two bolts. There is lateral play allowed to allow the shaft to run directly to the rear axle in a lateral sense.
I use a string to "string line" the alignment so that it doesn't have and additional angular "side jog" to articulate through. This can cause additional vibration.

4) The "vibros" might have been there all along 'cept you didn't notice it!
In cases like yours I road test the rig PRIOR to dis assembly and note the vibro retorts; then I have a set of chassis ears from Snappy to "listen" to the creaks and groans of the frame when under way and driving long at the speeds making all the noises.
Dennis

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Thanks for the feedback Dennis! Re your comments:
1) I will have an opportunity to get under the van in a couple of days and about 350 miles. You seem to be saying it will be apparent. If something seems amiss, I will attempt to correct it. Do you know what the torque specs are for the U/J bolts?
2) I assume I can detect any brinneled bearing by feel? Any bearing that didn't feel perfectly smooth would require replacement, right?
3) I can do the string test too.
4) I'm pretty certain this is a new vibration. I noticed it the moment I got on smooth pavement at highway speed.

What are your thoughts on continuing to drive this vehicle in regards to 1) causing a catastrophic failure, and 2) causing additional wear & tear on drive train components. When I finally get things back to normal, do I need to be concerned about having reduced the service life of things like U/J bearings, transmission and differential seals, shaft support bearings and seals, etc?

Thanks again; if I were a little closer to CO, I'd consider hopping on over there and have you take a look at it.

Wayne.
There are two opportunities to get it wrong. they are the splines on the shafts. The statement that the tech marked things is most likely a hope rather than fact. There are arrows in the forgings on both splines. If there do not line up then that is your problem. Then its up to you to decide to take it back or do it yourself. Eric

Wayne
Eric thumbup:mate ) has like me has mentioned the first and most likely culprit U/J yolk mis-alignment by not getting the splines on the shafts stubs aligned correctly. You can see that by eyeballing them like a row of tin soldiers from under the vehicle.
Not rocket science!

The tights spot can often only be eliminated by U'J replacement or in some cases by simply using the vehicle the wear areas MIGHT get worn over the long term use and smooth it all out!

Off topic but relevant we find the same potential issue when converting a Range Rover to steel suspension. Converting to a higher stance is popular but the new prop angles cause a new found vibration which can be a complaint source.

Continuing to drive the vehicle is a judgement call.
All abnormal vibration should be investigated because it has the potential to get worse.
If only for peace of mind!
Again a general statement by harking back to Landrovers again I often tell customers who call in about this issue to get it checked or bring it in. A statement that always rings true in any situation.
On the Discovery 2 model the front prop has a notoriety to start to emit a subtle vibration often overlooked but quickly develops and detaches itself blowing a big hole in the transmission ($$$$$$$) and beating big dents in the floor! Ouch!

Of course having been in this business for more than half a century, olde tyme mechanics will have horror stories to tell.
When I was 18 in a big truck shop as an apprentice the foreman had me take over a job of putting a clutch and the gearbox back in an 8 wheeler and trailer loaded with H2SO4.
The bloke who tore it to bits had all the bolts etc in a box. I used them all to put it all back together except one! A 5/8 plug bolt with a nose extension on it! a rogue bolt --I couldn't find out where it went!

What I didn't know was that the prop centre bearing had been slacked off and the whole assembly slide sideways on the tubular X member. That plug bolt was the alignment pin for the centre bearing!
After the truck had gone Tom my mate who tore it a part was back from college and I asked him about the bolt???? Alarmed he called the Foreman Bill who had fought Rommel's German Afrika Corps in North Africa with the Desert Rats. Nothing phased this bloke but even he was concerned.
After a quick phone call to the truck company we were informed that the prop had just fallen off, ripping out the pipework on the main tanker and 10,000 gallons of H2SO4 has been discharged onto the motorway heading into South Wales! Oh FFS

Bill having been a Company Sgt Major had a typical British Army demeanor gathered us all together in the shop and stated
"Laads don't do that again there's good gentlemen!" We have half the effing fire brigades in the country cleaning up acid and this has to be almost a big FUp since Dunkirk where the British Aaarmy didn't do very well. Don't let it happen again allriiiigt!

From that day to this I still check all work going out the shop just in case and all vibration is checked. Life's lessons! Crikey!
Dennis

Thanks Mike and Dennis! Great story Dennis; it's a bad day when you don't learn something new and that was a good day for you!

Either of you happen to know what the torque specs are for the U/J bolts? I expect to be under the van tomorrow, assuming the whole thing doesn't blow up on me during the 350 mile drive I have ahead of me.

wayneskid,
Might want to pick up a set of the bolts.
They are trilobular "one use" self locking bolts I'm pretty sure.
Send me your VIN # and an email address to return your data card and I'll look up the part numbers for the bolts if you like.
Hope this helps,
Roger

Roger, I sent you a PM yesterday with VIN & email.


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UPDATE - I've now completed a bit over 1400 miles since the driveline work in CA and ready to put the van back in storage in OR. The miles were completely uneventful but the vibration is still there. Once I return home to AK I will be discussing with the dealer a plan of attack for resolving this issue. They seem pretty willing to do whatever I want and will reimburse me for any out of pocket expenses if I choose not to bring it back to them. I'm trying to figure out what I want to push for here; both the question of what to do and where to have it done. If an inspection reveals that all the parts were re-assembled in the correct alignment, then what? If this is the case I think the service manager is going to suggest rotating the shaft 180 deg. If the vibration is gone then MAYBE all is well. But, it would be entirely subjective. Should I request a dynamic balancing of the entire driveline? The folks at Sprinter Store/Upscale Auto tell me they use a driveline specialty shop that will do that.

I won't be using the van for a few months so I have ample time to come up with the best plan.

Sure would appreciate any thoughts!

Wayne,
Whenever I've had a driveshaft vibration, my Sprinter has been under warranty, and once we go through "the process" (Step 1 change out the carrier bearing on the
OEM driveshaft....Step 2 Get MB Compliance Engineering to authorize a warranty replacement of the driveshaft) I get a new driveshaft installed.
I've done this on all 3 of the 170" wb (4325 mm) 519/516 series Sprinters I've had.
Since you are probably out of warranty, not sure how this will work for you, but getting them to ensure that all the components are aligned correctly is definitely the first step.
As suggested, if you could get the MB/Freightliner dealer to authorize removal of the driveshaft and having it checked/straightened if required/balanced as a 3 piece
assembly that might be the ultimate solution.
I've suggested this as a lower cost (to MB USA) solution a couple of times but they continue to replace the brand new drive shafts under warranty.
Hope this helps,
Roger

The two carrier bearings were replaced under my ELW; I recovered about half the cost of the ELW. I think I will see if they will replace the shaft with new.

Thanks,
Wayne


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