T6 4Motion differential catastrophic failure

[Fluff34567]

Two cases the same straight after servicing, I’d take a wild guess and says it looks like some ambiguous training / documentation in use by VW.

No surprise, even reading the service sheet on page 2 of this thread causes confusion

 

[matichile]

Mine did the same, but took some 5.000 km after servicing. It broke in half and even catch on fire. Still on repairs, after one year. Turns out to also blown the front differential when they tow it.

 

[Marius Boersma]

Hello,

I'm in trouble with my T6 and as far as I can tell it's a fairly unique problem. Any advice or insight would be greatly appreciated.

~4 Months ago I bought a lovely 2018 T6 Camper (converted), bi-turbo, 7 Speed DSG and 4Motion with 70k miles / 115km on the clock. I got it serviced as the timing belt was due, as well as new fluid in the DSG box and diff. This was at a mainline dealer here in Dublin so it wasn't a cheap service but I intended to keep the van for a long time. They said the flywheel was starting to go so I took it back to where I bought it and they kindly fitted a new one. Not the best start but ok so far.

Fast forward 2000km later and while driving down the motorway the rear differential exploded. I mean literally exploded, the housing is ripped in two (see picture), it tore itself off it's mount and where the drive shaft goes into the unit the housing is twisted about 1/4 revolution. There's also grease all over the sway bar just in front of the diff. I'll attach more photos tomorrow when there is some light.

View attachment 173929

There was a loud bang and a pretty violent jerk when it happened. We pulled in thinking it was a flat tire (or multiple flat tires given the noise) and the rear underside of the van was drenched in oil. We were just leaving a tollbooth and had the van just back up to speed when it happened. Didn't tear away or anything, just gently back up to speed. Nothing on the road either that could have hit it. I'm glad we were going in a straight line and not in the middle of a bend as the rear wheels locked up momentarily.

Has anyone come across anything like this before? The twist is I never asked the dealership for a diff service. I wanted the fluid in the Haldex clutch changed but that got mis-translated as a diff service. I only realised the mistake after this accident by looking at the part numbers on the docket for the service. I have read a few reports of Haldex fluid being mistakingly added to a diff and the diff going bang ~1000 miles later which seems very similar, but the back of the van is covered in gear oil. Granted I have no idea what Haldex fluid is like but it looks like the diff has the correct oil in it from the part number in the docket.

The van is sat at home for now. I got a preliminary quote for a new diff from VW but it's obviously silly money, 7k just for the diff and labour never mind whatever else is broken. Is it possible to delete the 4Motion diff and convert to 2WD?

Any insight / advice would be greatly appreciated. Thanks for reading.

Same happened to me. Currently at dealer for repairs.
Mine after mine within 1000km after service. 60 000km on.
2019 T6 Caravelle. Diff oil were changed.

 

[RadekZ]

Was the correct differential oil used? G052145S2 or G060517A2?
It looks like the differential overheated and then exploded.

 

[StevenD]

@Marius Boersma @matichile I'm sorry to hear about your vans, believe me. I know 3 diffs exploding isn't a lot, but from reading / talking to mechanics I gather a diff exploding is pretty much a freak thing. I finally got my van repaired by a specialist and it's the first time he had seen something like this. If these diffs are exploding with small mileage and the correct oil then something is badly wrong.

In my case the correct oil is on the service invoice, G060517A2. I still don't know how thay managed to service it though.

An update on the story. I collected the van back before Christmas. I was unable to source a second hand unit so had to pay for a new unit. The diff + haldex, prop shaft and two half shafts were all replaced at a cost of 8700 euro. Not nice at all but at least it was all done correctly. Thanks again to everyone who helped with links and info.

The diff is with an engineer for analysis but once again things have stalled there. I was hoping to wrap up this thread with an explanation of what went wrong but no luck so far. I will follow up when I know more.

 

[HossP]

It is great that you were finally able to get it fixed.
I appreciate that many may not like to hear this, but IME as a diesel mechanic is that sometimes the mechanical gods just decide to not play nice.
Our workplace ran a huge fleet of cars, trucks and earthmoving machinery. Everything was serviced impeccably, including overservicing of machines that did very little work due to their speciality and did not do many miles, so we effectively changed fluids that had done very little work.
We still had failures that had no explanation or no clear cause. Though as things got more technically complicated over my 35 yrs I found it more difficult to pinpoint the source. In the ‘older days’ it was normally pretty easy.
You may get no definitive answer sadly.

Good luck.

 

[StevenD]

Hi @HossP

Thanks for the message. Yes I appreciate your point. The fact we had the van for only 3 months, spent so much money on it and again spent a lot getting it fixed it made me search hard for someone to blame. It most likely was just the mechanical gods at play. I've sold the van, failure and fix fully disclosed of course, and given up on pursuing any sort of technical assessment.

If (big if, but there aren't many good options in Europe) I do buy another VW I'll go for a much simpler one.

 

[@KC1]

Hi @HossP

Thanks for the message. Yes I appreciate your point. The fact we had the van for only 3 months, spent so much money on it and again spent a lot getting it fixed it made me search hard for someone to blame. It most likely was just the mechanical gods at play. I've sold the van, failure and fix fully disclosed of course, and given up on pursuing any sort of technical assessment.

If (big if, but there aren't many good options in Europe) I do buy another VW I'll go for a much simpler one.

Hi Stephen,
Sucks to hear about your troubles, it’s a shame you had to sell the van and had so little quality time with it. I’m also based in Dublin, also have a T6 4 motion with 87k, also have had nothing but issues since I got it 8 months ago, injectors/glow plugs/ DPF. I’ve given up on the main VW dealer in Dublin (i’m sure you know who I mean) as they are useless and VW used warranty is a joke. Thankfully no drivetrain issues so far but… with that in mind can you forward the details of the local specialist who do the work for you. Thanks.

 

[StevenD]

Hi @KC1, also sorry to hear about your troubles. I'm starting to think the Euro 6 stuff VW is putting out just isn't up for the job. Or maybe that's just how it appears to me having owned nothing by Japanese vehicles until now. I got talking to a mechanic recently by chance and he claimed the 4Motion systems do give a lot of trouble, at least as far as he's seen.

The specialist I ended up with was Active Transmissions, but they are purely for gearboxes, diffs etc, so I doubt they would be of much help for your issues. I gather mine was just a plug-and-play job in the end, nothing was salvageable but I was still very happy with them. Very professional and patient.

 

[DXX]

We still had failures that had no explanation or no clear cause.

Oh yes, I worked with marine machinery for decades and there were many cases where the ‘fairies’ were obviously unhappy. Despite trawling back through maintenance history and many long accident investigations a few were still unexplained. Then you look at CCTV recordings and hear a few drunken confessions in the bar at crew change!
Human interaction causes a wealth of fk ups, getting a straight, honest statement from the guilty party isn’t always easy and can waste time and $$$$ in follow up maintenance and inspection.

 

[@KC1]

Hi @KC1, also sorry to hear about your troubles. I'm starting to think the Euro 6 stuff VW is putting out just isn't up for the job. Or maybe that's just how it appears to me having owned nothing by Japanese vehicles until now. I got talking to a mechanic recently by chance and he claimed the 4Motion systems do give a lot of trouble, at least as far as he's seen.

The specialist I ended up with was Active Transmissions, but they are purely for gearboxes, diffs etc, so I doubt they would be of much help for your issues. I gather mine was just a plug-and-play job in the end, nothing was salvageable but I was still very happy with them. Very professional and patient.

Thanks Stephen, my issues are all sorted now, for the moment, handy to know about Active Transmissions in case I need it in the future…

 

[HossP]

Oh yes, I worked with marine machinery for decades and there were many cases where the ‘fairies’ were obviously unhappy. Despite trawling back through maintenance history and many long accident investigations a few were still unexplained. Then you look at CCTV recordings and hear a few drunken confessions in the bar at crew change!
Human interaction causes a wealth of fk ups, getting a straight, honest statement from the guilty party isn’t always easy and can waste time and $$$$ in follow up maintenance and inspection.

Guilty parties lol. Just before I retired we got called out to an Acco tipper that ‘wouldn’t start’. Got out and the engine was locked solid, the gearbox was locked solid, the diff was locked solid.
Driver and his mates on the roadcrew said it ‘just stopped.’
After a few hours the truth came out. The oil pressure light came on and the driver stopped and checked the oil. It was fine. So he kept driving, even putting his packet of cigarettes over the spot where the oil light was annoying him.
Eventually it stopped (seized). Wouldn’t turn over on the starter. So they thought the battery was dead, hooked it up to a grader and towed it up a hill. Then tried to roll start which smashed a gear in the gearbox.
Repeated the process which broke the pinion in the diff.