T6 4Motion differential catastrophic failure

[Salty Spuds]

@yeha thanks a lot for sending that on, it's the best value unit I've seen so far. The van finally went in yesterday to be looked at so I'll see what they say before I go ordering parts. The one you linked looks like the best option anyway. There is a load of them in Germany but for a good bit more money.

@Salty Spuds I've been using the manuals from erwin specific to the van and there is no mention of a maintenance for that diff, or an interval. We all know that's not really sensible though and I expect the dealership would argue just because it's not in the manuals doesn't mean it shouldn't be done. I have to wait and hear back from the garage before I can do anything anyway.

Re. The maintenance. I’d expect to see something one way or the other in the maintenance docs. Either a maintenance schedule or some kind of statement to the effect of “The differential is sealed for life & requires no routine maintenance”. It would be very strange if they just ignored it. It’s a fairly complex & expensive bit of kit, I’d be very surprised if it wasn’t covered.

 

[StevenD]

I agree it's strange. I've found that getting maintenance schedules for the T6 to be pretty frustrating until I discovered Erwin, so maybe I've overlooked something. On the Erwin portal I did find a pdf that lists maintenance items and intervals (it's the same one found in the downloads on here) and there is no mention of the differential (aside from a warning about using mis-matched tires). It does mention the Haldex unit which they refer to as the "All wheel drive coupling". Aside from Erwin I've not had much luck finding maintenance information. Haynes doesn't have a manual for the T6 and googling generally only turns up forums posts. Erwin should be definitive though as it comes from Volkswagen themselves.

Maybe comprehensive serving information is only accessible to authorised dealers now? I'm not sure how else they would have found a service item for the diff if it wasn't on their system somewhere.

I bought VIP here and had a look through the downloads and didn't find anything. The t6 owners manual does say

All service fluids and consumables, e.g. toothed belts, tyres, coolant, engine oil, spark plugs and vehicle batteries, are being constantly developed.

I guess VW doesn't count diff oil as a "service fluid"? I've heard the attitude of car companies these days is if a parts lifetime is longer then the vehicle warranty they no longer care about service / maintenance for it.

 

[DXX]

Commercial fleet owners don’t want vehicles off the road under maintenance losing production and acquiring maintenance costs.
Once it’s passed it’s lifecycle within business nobody cares about the reliability.

 

[Jan_H]

The cause of the Haldex clutch timing case cracking (in the ribbing) is due to the mechanic accidentally draining oil from the timing gear instead of the Haldex clutch. But add oil to the Haldex clutch (a small amount). The vehicle will run with residual oil in the transmission for approx. 3,000 km and then the mentioned Haldex clutch distributor cap ruptures. Here is the link to gearbox specialist who described these types of issues on all Haldex generations, but is in czech but you can use translator HALDEX spojky

 

[StevenD]

@Jan_H What you describe is also what I thought but I don't think it's possible to prove the diff was out of oil/low on oil. I'm still waiting for the shop to look at it, when they get around to it maybe I can get some photos of the inside.

My new problem is finding a diff. Turns out there are a lot of revisions to these units and none of them are interchangeable. The part number on every diff I've looked at starts with "ZSB 09N 525 010" embossed on the casing, but there is a letter etched/stamped in after that, so faint I didn't notice it at first. I have a "H" model diff and can't find any for sale without huge milage on them or for big money.

I'm skeptical these diffs were revised every 1 to 2 years to the point where they are incompatible but every breaker / seller I've contacted told me it has to be a "H". This is what VW say anyway.

@yeha, or anyone else who might know, when you replaced your diff did you use a unit with the exact same code? Even if it can work I'm wondering if it's locked out with software.

 

[yeha]

The F & H models are without difflock. The G & M are with. They all share the same cradle and shafts. On the T6 gen 5 Haldex, the controller only has a pair of connectors, one from the vehicle and one to the pump, and just happens to mount on the side of the diff whereas the T5 mounted the controller into the casting as it has a control valve attached. If you are that concerned, simply swap your ecu across.

 

[StevenD]

Thanks for the information. Can I ask how you know? I've also seen some K and L models that look good but not sure they will work.

 

[yeha]

I just spent far too much time on 7zap or Nemiga dredging through the parts catalogue gathering info. Unfortunately the available online catalogues seem to stop at 2016.

 

[Fluff34567]

Lots of different pics here regarding the fill and drain plugs. For a gen 5 unit the drain plug is near the pump and fill plug is on the other side about 10cm back from the control box.

Photo is stolen from mmi !

Drain plug

 

[StevenD]

@Fluff34567 pretty sure that's the drain and fill for the Haldex, not the diff. It's confusing!

 

[Fluff34567]

Yep thats haldex, couldn't find a proper fill drain for the actual diff, or oil spec.

 

[StevenD]

Latest update. This has been pretty slow to progress. Took weeks to get it up on a lift for an initial assessment, now I'm waiting another week for a solicitor to get back to me.

So far the unit is still in the van. I want to arrange to get it out and an engineer to look at it. Before I do that I want to talk it over with a solicitor. The garage that did the incorrect service aren't interested in doing anything aside from taking a lot more of my money. But I want to make sure I don't waive any rights etc by having someone else remove the unit. Every step takes weeks before I get a response that allows me to move forward. I've put up with the delays in the hope a suitable unit will pop up for sale during that time but no luck so far. There are some in Poland but the details are pretty scant. All of the units I've found on Allegro have signs of damage or are collect only with the seller not interested in shipping. That seems kind of suspect. I also found some in Sweden so that might be worth a look.

At the moment if looks like my options are spend ~10,000e on a new diff and all the other parts and have a professional fit it. I'll most likely sell the van after as it's simply too much money.
Or I can risk a diff from Poland but so far nothing suitable has shown up.

 

[rod_vw]

I just spent far too much time on 7zap or Nemiga dredging through the parts catalogue gathering info. Unfortunately the available online catalogues seem to stop at 2016.

Try looking here IFI :: Free services

• Click CarProg2
• Select the vehicle that you want to view
• Work your way through>>>

 

[StevenD]

@rod_vw thanks a lot for sending that on. CarProg2 has information on the T6s. At least it sheds some light on all the different models of diff. It should also help with finding used draft shaft, half shafts etc. Those all come to about 2k new so at least now I can see if different vans might have the same bits.

 

[Paynewright]

Have you tried the ebay sellers - Kernow or Cotswold T6? They seem to have a lot of parts from broken vans (tailgates, seats, full interiors etc)

 

[rod_vw]

@rod_vw thanks a lot for sending that on. CarProg2 has information on the T6s. At least it sheds some light on all the different models of diff. It should also help with finding used draft shaft, half shafts etc. Those all come to about 2k new so at least now I can see if different vans might have the same bits.

Despite being a bit of a trial to get where you want to go I find it one of the best parts info systems available. It shows the Crafter (although mine is a TGE) right up to 2023 models and maybe some info on 2024.

 

[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.

Hello Stevan.
I am from South Africa. The same happened to me the day before Yesterday. My 2019 Caravelle 4 Motion is currently at the VW dealer. They open for bossiness tomorrow. I will let you know the out come.
It has 60250km on the clock.

 

[Fluff34567]

Hello Stevan.
I am from South Africa. The same happened to me the day before Yesterday. My 2019 Caravelle 4 Motion is currently at the VW dealer. They open for bossiness tomorrow. I will let you know the out come.
It has 60250km on the clock.

Did you have a service recently?

 

[Marius Boersma]

Did you have a service recently?

Yes

 

[DXX]

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.