Hello folks... I really like my Doblo, but recently it's become more of a Woblo.

After a month or two of fruitless toil, my 2003 JTD Cargo continues to wobble. Please forgive the length of this post, but I thought it best to include full details on the symptoms, and my as-yet fruitless attempts at curing the problem:

The Symptoms:

Moderate to severe wobble/shake on acceleration in all gears from about 1500 RPM upwards. Particularly apparent in 2nd & 3rd gears, but if I put my foot down in any gear the shake will result until I ease back on the accelerator.

No wobble whatsoever when coasting out of gear at any speed, (or with clutch depressed). No wobble when stationary at any revs, so hopefully not clutch or DMF.

Wobble felt through seats, floor, but not really through the steering wheel or gearstick. FEELS like it's coming from the front of the van but it's hard to say. Also difficult to say whether the wobble is side to side or front to back etc. I estimate that the shake oscillates at 4 to 6 pulses a second. It's not pleasant!

Wobble happens only when accelerating straight ahead or turning left (worst). No wobble at all when turning to the right. So turning on to roundabouts I get a wobble, while on the roundabout no wobble, when I turn off roundabout the wobble resumes.

The greater the load (eg uphill) the more severe the wobble.

The only way I can get the wobble to lessen (though it's still there) is to carry a passenger (or presumably a heavy sack of something) in the cab with me. The added weight on that side of the front of the van seems to quell the shaking. Or to accelerate very slowly through the gears. Or just go round clockwise circles.

Steering, braking and general handling otherwise seem normal. There's no visible play in the steering, and that's not where you feel the wobble anyway.

The engine pulls like a train so I don't think it's the problem. The gearbox had new bearings and diff gears last year, and the gearbox guys who did the work don't think the problem lies in the box.

When sitting on axle stands, and the wheels driven, the wobble can still be felt (though fainter) so I'm suspecting that it's not a problem from the rear axle. Obviously the load is less when the wheels are dangling in the air.


Things I've tried so far...

Wheels (original steel) and tyres all thoroughly checked, tested, balanced. Tracking checked. All wheels inflated and tightened correctly.

All four wheel bearings are quiet with no free play or noise when spun and shaken top/bottom, forward/back, and side-to-side.

More than one garage has inspected all visible suspension/steering bushes, joints, links etc and can find no wear. Crowbars have been applied to wishbones to check for free play.

Top and bottom gearbox mounts have been changed.

N/S driveshaft inner CV tripod joint replaced by independent Fiat specialist. When this didn't help, I got an entire new driveshaft fitted on the O/S. No improvement. So both inner CV joints are new. The van turns in tight circles in both directions, backwards and in reverse with no clicks or knocks.

As I say the only thing that seems to help is when I'm carrying a weight in the passenger seat. I guess that if this was LHD, I wouldn't have a problem!

No one I've spoken to seems to think that the shock absorbers are likely the cause, and there are no nasty squeaks when I bounce the corners. It did occur to me that the upper suspension mountings or shocker bushes may be the culprits, but would they be capable of causing the shake/wobble?

In wet weather (and only when I'm traveling passenger-less) I sometimes get a metallic click or tap coming from the passenger footwell area when I step on and off the accelerator. This may or may not be related to the wobble. I hoped that the new lower gearbox mount would cure this, but a drive today in the rain confirms it's still there.

The gearbox people say they don't think that the problems in the diff as the wobble's there when accelerating straight ahead. The best they could suggest was to try replacing the N/S driveshaft completely, though as I say the inner CV joint is new. I think they were stumped.

The van passed its MOT back in December with no advisories (the wobble was evident at that stage and I had a local garage inspect the front underside prior to the MOT test).

Sooooo...

If anyone has managed to take all of this info in, and has any idea where I should investigate next, please chime in and I'll try to get this van back on the straight and narrow. I'm concerned that the shake will get worse and result in catastrophe.

Likewise, if anyone can recommend a good logical thinking intelligent motor mechanic (in or around NW London) who might be able to troubleshoot the problem, my ears are very much open. So far all the places I've been have been well meaning, but unable to diagnose the fault.

Thank you very much for reading this!

Well, to me, it seems obvious it is drive shaft related!

Reason I say this, I own an XK8 of 2004 vintage. I bought it smashed at the front & it took me 14 long months to get the parts together to fix it.

Anyway, long story short, it does EXACTLY the same, but upon deceleration and there is only 1 possibility:

Prop shaft output flange got twisted (the prop was like a boomerang) by 1 or 2 mm. However, It doesn't bother me as it only goes mental when I lift off above 100mph. Anything less is fine, so no run round the "Ring" for me

My guess is the flywheel or clutch assembly is about to let go.

It isn't the first time a flywheel has come loose. My friend almost lost hes feet when the flywheel came off at 70mph in his Sierra Cosworth. It shattered the bell housing & all hell broke loose with rear wheels locking up, but he was too busy keeping his feet clear of the buzz saw like flywheel spinning through the footwell......

Not trying to scare you, but that's a worst case scenario.

I would be looking first for loose shafts at the gearbox end. They may well be floating by a mm and when you accelerate, the diff will oscillate.

Also, check the bushes at the front subframe, any wear in there will magnify the vibes.

I am inclined, however, to think it is the clutch assembly, especially if it lessens when you press the pedal.

But it's a hell of a job to diagnose sitting here on holiday in Tenerife!

22/26 degree's C, what can I say, it's awful

I had another thought as I was eating food that was awful.....ly good :slayer:

What about the NS shaft itself?

I know you replaced the inner/outer CV's, but what if the shaft itself is somehow damaged?

Has anyone checked the front crank pulley? Plenty times I have replaced Peugeot/Citroen diesel DMF pulleys that made a racket and occasionally would vibrate.

I even had a Renault 5 TX years ago with a water pump pulley that had somehow been damaged (careless mechanic we think) and it used to vibrate at a certain RPM. New pulley sorted it.

A quick way to check if its a belt pulley is to temporarily remove the drive belt. If the vibration stops, spin each pulley by hand and see if it wobbles.

Also, see if the crank pulley wobbles noticeably at idle and with someone applying gentle throttle.

And finally a long shot: What if an injector (or more) is sticking just enough to cause a fuel shortage, but not flag up a MIL?

I would suggest a live data reading to see what the injectors are playing at?! Perhaps someone with an oscilloscope could measure the pulse width & frequency to see if there is a problem....

Best I can do for now buddy

Well.... N/S shaft is being reassessed on Thursday by the (Fiat/Alpha specialist) garage that repaired its inner CV. I'll also get them to look further afield as per your other suggestions (inspired by that fancy nosh:yum.

I was under there today re-checking everything in sight for solidity and soundness, and really can't find anything even vaguely loose or any cracking rubber bushes.

There is a tiny amount of play if you grasp and shake the driveshaft cv (tripod)cup-holder as it enters the gearbox, but having spoken to the gearbox people who sorted the box bearings and diff gears out a year ago, they said this has to be so to let gb oil around the shaft/splines. I'll see what the garage have to say about that.

Engine seems to be running and pulling well, though there is a slight oil leak somewhere (haven't had to top it up since last oil change in early December though). Leak is from the pulley-end of the block, but not on the alternator belt, and the pulleys all seem to go round nice and true.

There's maybe also an air leak somewhere as MAF output voltage reading is a bit erratic in Multiecuscan, and the "actual" air quantity reading is never more than a third of the "required" air quantity. I'm trying a different MAF sensor (when it arrives) to rule out that it's a bad MAF. I've had no luck tracing the leak by spraying carb cleaner around all air intake and pipes/joints (and turbo area) to listen for rev rises at idle.

Air intake, filter housing, MAF, MAP sensor all clean. Cleaned EGR last summer.

No shortage of power on the road though. Just a ruddy great wobble/shimmy in the process.

Dobbler said:

Well.... N/S shaft is being reassessed on Thursday by the (Fiat/Alpha specialist) garage that repaired its inner CV. I'll also get them to look further afield as per your other suggestions (inspired by that fancy nosh:yum.

I was under there today re-checking everything in sight for solidity and soundness, and really can't find anything even vaguely loose or any cracking rubber bushes.

There is a tiny amount of play if you grasp and shake the driveshaft cv (tripod)cup-holder as it enters the gearbox, but having spoken to the gearbox people who sorted the box bearings and diff gears out a year ago, they said this has to be so to let gb oil around the shaft/splines. I'll see what the garage have to say about that.

Engine seems to be running and pulling well, though there is a slight oil leak somewhere (haven't had to top it up since last oil change in early December though). Leak is from the pulley-end of the block, but not on the alternator belt, and the pulleys all seem to go round nice and true.

There's maybe also an air leak somewhere as MAF output voltage reading is a bit erratic in Multiecuscan, and the "actual" air quantity reading is never more than a third of the "required" air quantity. I'm trying a different MAF sensor (when it arrives) to rule out that it's a bad MAF. I've had no luck tracing the leak by spraying carb cleaner around all air intake and pipes/joints (and turbo area) to listen for rev rises at idle.

Air intake, filter housing, MAF, MAP sensor all clean. Cleaned EGR last summer.

No shortage of power on the road though. Just a ruddy great wobble/shimmy in the process.

Click to expand...

This is a diff issue, what happens is the spider on the driveshaft wears a grove in the guide it slides in, in the diff, so, when you turn etc the spider goes in and out of the groove, take shaft out and feel along the diff guide, bet there will be a groove.

regards

Mal

Mal126 said:

This is a diff issue, what happens is the spider on the driveshaft wears a grove in the guide it slides in, in the diff, so, when you turn etc the spider goes in and out of the groove, take shaft out and feel along the diff guide, bet there will be a groove.

Click to expand...

OK thanks, Mal. Just so I understand a bit better ....

The spider joint itself sits in a cup (near end of driveshaft) that it slides in and out of, but the cup is part of the shaft. The only bit of the DS that enters the diff/gearbox is the splined end. Any groove that the worn spider (tripod?) makes will be in the bearing cup. The tripod joint has already been renewed, but the cup holder hasn't. If they pull the driveshaft out, take the inner joint to bits again, what you're saying is that they'll find a groove in the cup? Or am I misunderstanding you? Can the cup be renewed, or is it new DS time? Or is it (gulp!) really diff damage (£££s)?

Thanks guys for taking time to help on this one!

Ma has just said what I tried in a long and beer infested way, but failed the first time :worship:

As I understand it, he's saying the cup that holds the tri-ended bearing section is f****d.

The bearings have likely worn the innards of the cup to the extent that the tri-ended section (or spider) are moving around too much.

So, when you accelerate, the shaft is being thrown about, creating the oscillation.

I guess it's like welding a nut on the middle of the shaft and once it reaches a certain RPM, a harmonic resonance (fancy way of describing a wobble ) is causing your trouble....similar to a wheel vibrating at 60mph.

But big drinks to Mal for getting it right when my booze addled arse couldn't

I do hope you're (both) right!

Thursday will be the day of reckoning .... :chin:

Dobbler said:

OK thanks, Mal. Just so I understand a bit better ....

The spider joint itself sits in a cup (near end of driveshaft) that it slides in and out of, but the cup is part of the shaft. The only bit of the DS that enters the diff/gearbox is the splined end. Any groove that the worn spider (tripod?) makes will be in the bearing cup. The tripod joint has already been renewed, but the cup holder hasn't. If they pull the driveshaft out, take the inner joint to bits again, what you're saying is that they'll find a groove in the cup? Or am I misunderstanding you? Can the cup be renewed, or is it new DS time? Or is it (gulp!) really diff damage (£££s)?

Thanks guys for taking time to help on this one!

Click to expand...

Yes, the cup thats sits in the diff, think is d/shaft only, cant get seperate, but make sure is fault before replacing, Good Luck and let us know.