Rear Diff / Haldex Issue

713 Views 33 Replies 6 Participants Last post by VelovetAndy, 12 d ago

Metcalfe

Discussion Starter · 1 mo ago

Hello, new MK5 owner here and having a nightmare with the car….

Car was shaking erratically suddenly at ~70mph and started spewing oil. Rear diff had shattered.

Since bought a replacement Haldex / rear diff and had it fitted. Car was working great. No issue for about 200 miles then same thing has happened.

To say I am gutted is an understatement.

So it was working for a short period of time. Car is currently waiting to go back to the garage.

I am worried it was the oil after reading similar on here. The oil used in the Haldex was FEBI BILSTEIN 101172 850ML HALDEX OIL. Is the oil in the rear diff different? Does it need replacing at the same time? I am not mechanically minded and the Haldex system and diff setup is new to me. Assuming it was the same thing.

Don’t feel I should be in a position to tell the garage which items and how toreplace.

Any ideas / help much appreciated.

Steven

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VelovetAndy

· #2 · 1 mo ago

A few questions. Presumably the replacement diff and Haldex were second hand . Also , presumably your garage does know that there are two oil chambers, one for the differential which takes the usual EP oil ( 90 I think but would need to check ) and the Haldex unit which takes the rather specific oil you mention in your post . The fact that you have now had the same failure on two completely different units is also suspicious. As you had a garage to do the work, I think they need to remove the unit and inspect it very thoroughly. Both they and you need to understand why this failure has occurred as you now have to go to the time and expense of sourcing yet another diff and Haldex .
One thing that does occur to me is that if there was some signal failure and the Haldex clutch became fully engaged , then the rear axle would try to spin at the same speed as the front. With no slip in the Haldex clutch, you would , in effect, have permanent 4 wheel drive but without the equivalent of a viscous coupling . Old school land rovers had a four wheel drive lock but could only safely be used on slippery ground where the wheels could spin independently . If that has happened to you , then something in the drive chain will let go. The weakest link would be the Haldex clutch . Exit one Haldex unit.
Which leads me to my final question. Is it the differential casing that has broken and is ‘spewing’ oil or is it the Haldex unit ?

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Metcalfe

Discussion Starter · #3 · 1 mo ago

Hi thanks for your help. Quality diagnosis.

Apologies for my lack of knowledge but the Haldex / diff unit is the same right? That's what was replaced, similar to this; VW Golf mk5 R32 rear diff with Haldex 7H0907554 | eBay

I had supplied the Haldex oil and the garage added the other oil. Car drove absolutely fine (better that previous) for 200-300 miles then it went.

Yesterday there was a high pitched 'whirling / squeaky' sound (presumably from the system) then a violent shaking then then it stopped yesterday. The car is back at the garage now and when recovered there was some oil leakage not sure where from.

This was the same as the original time it had occurred but a lot less oil.

Appreciate your help.

Steven

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VelovetAndy

· #4 · 1 mo ago

Yes. What you bought was the complete differential and the Haldex unit. However, they are two separate pieces of the rear transmission. The Haldex unit is the coupling between the front to rear transmission shaft and the pinion drive to the crownwheel and differential that drive the rear wheels via the two short driveshafts . The Haldex unit is effectively just a clutch , controlled by the main ECU which connects and disconnects drive from the prop shaft to the rear wheels. For 90% of the time, the clutch is disengaged and effectively our R32 cars are front wheel drive Golfs. Give it the beans or get on some slippery bits and the clutch will start to engage , transmitting a proportion of the engine torque to the back wheels. Hurrah, 4 wheel drive.
Right . Back to the plot. The Haldex unit can be ( easily ) unbolted from the differential unit ( the huge bit that bolts onto the subframe ) and be serviced or repaired separately . The remaining differential is a conventional diff running in its own hypoid oil . If your ‘ diff’ has once again thrown its toys out of the pram, back to my earlier question: you / your garage need to know which bit has broken ( Haldex or diff) and then why. The garage need to check the whole of the rear transmission system starting at the rear wheel bearings, back through the drive shafts and their joints, then into the differential and finally the Haldex unit and it’s clutch .

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Metcalfe

Discussion Starter · #5 · 1 mo ago

Garage have just confirmed the second diff has blown and there obvious damage to it so what you are saying is correct. I am waiting for some pictures which I will share but doubt they will help.

I think you are correct in what you are saying there is a major malfunction somewhere in the drivetrain and the force is exiting through the weakest point - Haldex.

The garage have contacts at VW they will speak to and will be running through the system to locate the issue as you have suggested.

Will let you know if I get any other information but again, your help is massively appreciated.

Steven

VelovetAndy

· #6 · 1 mo ago

Thank you. Glad the garage is on the case with the diagnosis. If you can, a few photographs would be useful, just to clarify if it is the Haldex and its housing or the differential and its casing. My instinct is that it is the former , but we will see. Connecting to VCDS May well help with Haldex fault code issues . I think that the system has been trying to run with a locked 4 wheel drive : exit one Haldex

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polo16v190

· #7 · 1 mo ago

Check the position of the driveshaft. Maybe it is not installed correctly, on the engine is moving too much (check engine mounts).

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R32Drongo

· #8 · 1 mo ago

I've done the service on the diff twice now and changed the haldex fluid too. I had put a less viscous oil in the diff 75w-85 instead of 75w-90. After 1000kms I decided to change it to the correct one, which has a higher rating GL5 instead of GL4. No signs of wear were found in the oil. The front bevel box had more fine particles however, so I put the expensive OEM in that one, since that works hard all the time.
So if your car is stock, its hard to understand why the actual diff gears would blow up. The haldex comes with an integrated controller, so the new one should not have had the same electronic fault (if it had one in the first place).
Did the workshop service the unit before it blew up the first time? If so they could be the reason, and they repeated the same error second time around.
But yes, find out if it was the haldex unit or the actual diff, and get the part back so you can inspect it and keep it for spares. Only other thing I can think of is if the car has some CAN device that tells the haldex to lock up constantly, but if you have had the car for ages, the problem would have occured long ago.

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Metcalfe

Discussion Starter · #9 · 1 mo ago

R32Drongo said:
I've done the service on the diff twice now and changed the haldex fluid too. I had put a less viscous oil in the diff 75w-85 instead of 75w-90. After 1000kms I decided to change it to the correct one, which has a higher rating GL5 instead of GL4. No signs of wear were found in the oil. The front bevel box had more fine particles however, so I put the expensive OEM in that one, since that works hard all the time.
So if your car is stock, its hard to understand why the actual diff gears would blow up. The haldex comes with an integrated controller, so the new one should not have had the same electronic fault (if it had one in the first place).
Did the workshop service the unit before it blew up the first time? If so they could be the reason, and they repeated the same error second time around.
But yes, find out if it was the haldex unit or the actual diff, and get the part back so you can inspect it and keep it for spares. Only other thing I can think of is if the car has some CAN device that tells the haldex to lock up constantly, but if you have had the car for ages, the problem would have occured long ago.

Hi, thanks for the information.

My car is in stock and recently purchased hence the pain of these repairs. I bought it around a month ago privately - no issues at all. Within a week the shaking started around 70mph. Obviously the previous owner does not want to know. When removing the first unit the garage had said that there were bolts missing on the underside and looks like someone had been messing around with. Obviously the issue was known about and covered up.

I got the car straight into the garage after the diff effectively exploded and had the diff replaced (I work away a lot so left it with them until I returned last week). Within a couple of days 200ish miles if occurred again. Pretty furious at this stage but doesnt help so I am just actively trying to get to the bottom of it so I can use the car.

The garage serviced the new diff I bought second hand before fitting it and it was working without issue. Drove very well in fact. At the time of the second incident I did hear a high pitched 'whirling / squeaky' sound (presumably from the system) then a violent shaking then then it stopped.

Thanks for all this information I am passing to the garage who will be looking into it next week.

Will get the part back when I can and look over it in detail.

Steven

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VelovetAndy

· #10 · 1 mo ago

Yep.,The Haldex does have its own controller but needs dynamic signals from the cars motion to ‘decide’ what clutch engagement strategy to adopt . The sound you descibe just before the the second Haldex( or is it diff) gave up the ghost sounds like the clutch pack failing because the axle speed difference is forcing it to slip and the engagements oil fed clutch pistons are holding the clutch fully engaged. That is still my guess but your garage will know once they have all the bits on the bench

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Metcalfe

Discussion Starter · #11 · 1 mo ago

VelovetAndy said:
Yep.,The Haldex does have its own controller but needs dynamic signals from the cars motion to ‘decide’ what clutch engagement strategy to adopt . The sound you descibe just before the the second Haldex( or is it diff) gave up the ghost sounds like the clutch pack failing because the axle speed difference is forcing it to slip and the engagements oil fed clutch pistons are holding the clutch fully engaged. That is still my guess but your garage will know once they have all the bits on the bench

I hope they know it seems you know a lot more than them. Want a job 😅?

Metcalfe

Discussion Starter · #12 · 1 mo ago

Morning, the garage has looked further into the issue and has confirmed the diff has blown. I had passed on the details of all the items noted above (many thanks for providing) and they have confirmed there is no immediate apparent issue. They do no recommend replacing the diff until the overarching issue has been rectified.

They suggest either;

I have bought a faulty diff,
There is a possible issue with the transmission box?
There is a possible issue with the car locking into AWD and I need to take it to a AWD speciailist.

That said this is becoming a big issue for me now.

I am looking for more specialised places in the north east. They are going to recommend a place to me but if anyone has any ideas or reccomendations I am all ears. Surely someone has heard of a similar issue with the system in the past.

Image below of the hole in the diff (difficult to see but it is at the tip of the pen).

Steven

Wood Tints and shades Metal Rectangle Glass

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R32Drongo

· #13 · 1 mo ago (Edited)

Found quite a few with quick google search,
"golf R cracked diff" seems like errors at service with oil type or quantity affect the diff, and towing cause haldex damage ?

Destroyed Rear Diff

2017 Sportwagen (4Motion) Rear Differential Failure

Reddit:

https://www.reddit.com/r/Golf_R/comments/qonpfq

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VelovetAndy

· #14 · 1 mo ago

A garage with ‘vagcom’ would be a help because a scan would at least throw up any error codes which might help pinpoint the problem. Next,,I am afraid is that the complete diff and Haldex need to be removed . Then, with the Haldex unit removed from the diff, it is easy to both inspect the Haldex clutch and to split the diff casing and look at crownwheel, pinion and the 4 differential gears. As for a specialist, one 5 minutes from my door but I am in south Derbyshire do that is a fat lot of help to you.
Andy ( administrator on here ) might be able to help as he is in your area.

DubNurd

· #15 · 1 mo ago

It could have been screwed when you bought it... but they would have drained both old fluids out anyway and been replaced with the correct ones. if it was already failing, the oil would have had lumps/sparklies etc. If it had the wrong fluid in, or was empty, that should have rung alarm bells and they should have put in the correct fluid anyway.

The two fluids are OBVIOUSLY different - the Diff takes actual gear oil which is quite viscous, and the haldex takes special oil that is very thin, like auto transmission fluid. How much of each oil did they use?

Best to change the Haldex filter too and clean the screen you showed in the pic above.

Those diffs are actually pretty solid, as long as they have enough of the correct oil in... Even the forced induction guys don't seem to destroy them, same for the modded S3's with some big HP.

It's extremely unlikely that anything outside of the unit itself would cause this type of issue. Most Diff failures on MK5's are after being serviced (wrong) - plenty of google stories on forums, and plenty are after being done at VW. Too many "technicians" assume they know what they're doing and don't check the manual. Most of the failures online end up being a dry diff, and some where the fluids are in the wrong places. If the haldex was locked up when it shouldn't THEY should have noticed on a test drive (its very obvious) and you would have thought the car felt weird (they try to drive in a straight line around corners, and will shudder and bind when turning in carparks etc or you feel/hear the wheels skipping and clunking when one gets on a surface with less traction, like gravel or grass). The rubber couplings at each end of the cardan shaft should have issues well before the Diff does

"They said they did it correctly"... but if they don't know what correct is, how do they know if it's correct or not?

I'd put my money on them draining the oil from the diff and either leaving it empty, or putting the haldex oil in.

In your picture, I can only see a tiny crack, no hole??? How viscous was that fluid drip on the bottom? It should be pretty thick.

Tell them to collect the oil from both parts and have a look at what is in each, how different they are and how much there is.

They problem you have, is that you supplied the part - if it was them supplying, they'd be liable to fix it, regardless. It's a bit tricky now, but I be surprised if they didn't cause it.

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Metcalfe

Discussion Starter · #16 · 1 mo ago

Thanks for the above. Reading further into it, I am not fully confident the local garage I have used have applied the correct oils to the correct chambers, noting their proximity.
They had not completed any Haldex work previously…
They are also adamant they have done it correctly but now I am not so sure.
Furthermore, on the second diff incident I noted a lack of oil in comparison to the masses coming out after the first incident.
In addition, before I bought the car the Haldex was also serviced at a garage local to the previous owner. a non-VW specialist.
Have I been unlucky with oil changes done incorrectly. This is coincident with the issues others have experienced in the forum links above.
The garage my vehicle is currently at have also said if they remove the diff for me to inspect they won’t be able to move the vehicle as several other items will need removal at the same time. Therefore it can only be removed during replacement. Is that right?
Sounding a bit suspicious now.
Next step is a VW specialist.

Steven

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Metcalfe

Discussion Starter · #17 · 1 mo ago

DubNurd said:
It could have been screwed when you bought it... but they would have drained both old fluids out anyway and been replaced with the correct ones. if it was already failing, the oil would have had lumps/sparklies etc. If it had the wrong fluid in, or was empty, that should have rung alarm bells and they should have put in the correct fluid anyway.

The two fluids are OBVIOUSLY different - the Diff takes actual gear oil which is quite viscous, and the haldex takes special oil that is very thin, like auto transmission fluid. How much of each oil did they use?

Best to change the Haldex filter too and clean the screen you showed in the pic above.

Those diffs are actually pretty solid, as long as they have enough of the correct oil in... Even the forced induction guys don't seem to destroy them, same for the modded S3's with some big HP.

It's extremely unlikely that anything outside of the unit itself would cause this type of issue. Most Diff failures on MK5's are after being serviced (wrong) - plenty of google stories on forums, and plenty are after being done at VW. Too many "technicians" assume they know what they're doing and don't check the manual. Most of the failures online end up being a dry diff, and some where the fluids are in the wrong places. If the haldex was locked up when it shouldn't THEY should have noticed on a test drive (its very obvious) and you would have thought the car felt weird (they try to drive in a straight line around corners, and will shudder and bind when turning in carparks etc or you feel/hear the wheels skipping and clunking when one gets on a surface with less traction, like gravel or grass). The rubber couplings at each end of the cardan shaft should have issues well before the Diff does

"They said they did it correctly"... but if they don't know what correct is, how do they know if it's correct or not?

I'd put my money on them draining the oil from the diff and either leaving it empty, or putting the haldex oil in.

In your picture, I can only see a tiny crack, no hole??? How viscous was that fluid drip on the bottom? It should be pretty thick.

Tell them to collect the oil from both parts and have a look at what is in each, how different they are and how much there is.

They problem you have, is that you supplied the part - if it was them supplying, they'd be liable to fix it, regardless. It's a bit tricky now, but I be surprised if they didn't cause it.

I wrote my response out without seeing this and I am of the exact same opinion. Must be an oil issue. Thank you for taking the time to respond it is very useful.

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Metcalfe

Discussion Starter · #18 · 1 mo ago

Spoke to another company specialising in VW and they have mentioned that the control unit on the new diff may not be setup for the vehicle. I am speaking to Vasstech later this morning so hopefully get some more information.

Metcalfe

Discussion Starter · #19 · 1 mo ago

I have the vehicle booked into Vasstech, Durham in a couple of weeks. I have confidence in them looking at their reviews and speaking to them this morning. They will complete a thorough analysis, now just need to source another diff.

Thanks to all who have helped so far it is much appreciated.

Will keep you upto speed with the repairs and hopefully others with similar issues can use this thread going forward.

Steven

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VelovetAndy

· #20 · 1 mo ago

Pleased you are making progress.

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