NOTE: This unit is NOT A HALDEX, it is a Borg Warner. I used the term Haldex because that is basically what we all still call it. LOL Also I have a DSG teardown video coming soon! Be sure to like this video if you like teardown goodies!!! Thanks so much

We are Haldexrepairs in the UK, this Gen 5 haldex coupling is perfectly fine and has not failed mechanically. It is most likely to just have pump failure. The clutch is still totally good. But the most common part for coupling failure is actually the outer O ring seal on the piston you removed at 4:26 gets chewed up and leaks. That is pretty much the only thing that fails on them. Good luck! And we call it a Haldex even though its a Borgwarner Power Drive Systems G5 coupling due to licencing issues since Haldex AWD was sold to BorgW. Enjoy :)

Pump motor failed. Clean and reassemble with new motor and ride out. Those clutch friction discs aren’t too bad. Same type of multi plate wet clutch as motorcycles use. You can dress the steel plates by polishing them with some 400 grit paper glued to a surfacing plate. I have saved many dirt bike clutches this way that were much worse.

I had a loss of rear traction on my 2015 S3 and noticed the voltage to the motor was less than half of what it is supposed to be under full load. Replaced the motor with new fluid and it’s now working correctly, pushing 11.xx volts to the rear motor. Definitely a best first step if you’re dealing with this issue as the motors can be had for

I'm not a mechanic and would never go this deep on my own vehicle, but I love how you present things that I'll watch it anyways!

Charles....Check the pressure release valve at the top of the casing where the prop shaft flange meets the clutch pack housing....to the right of the HA1 casing mark at 2:11 to 2:37 in the video. See if it is clogged with debris...let us know...if you find anything there. Debris causing it to stick open = clutch slip and overworking the pump motor... then some type of failure. Also, after replacing a pump...the relearn procedure is omitted...leading to replacement of entire rear units...that would have otherwise returned to normal function.

A few notes and questions: -Clutch pack is available from Audi, about 600-700eur, but this pack didn't look too bad. I've seen some pairs that are fused together. -Pump is available from both borg warner and Audi, there are also service kits around for much less. Generally the brushes go bad, the pump can be tested with 12V. -The pump continuously runs when you start the car. Theres also a small pump / actuator inside the control unit with a plunger blocking/allowing the oil to flow and this is what controls AWD, probably that has failed as well. -You are correct, Audi europe service manual doesn't have a rebuild guide. But I have a Audi USA PDF that has rebuild instructions. There are no measurements for putting the haldex together but there are extensive measurements on the diff-haldex side, otherwise there will be noise when running. Now the questions: -Can you mix and match parts from two broken haldex/diff units? Eg clutch and plate pairs? -Especially, can you mix and match diff and haldex halfs? My mechanic says crown wheel and pinion are "married" with each other and you can't match them, it will be noisy. I have a broken awd that no longer works on my Audi TT mk1, AWD works on the lift but on the ground the rear wheels don't engage... Haldex fluid was pitch black last time I checked it.

I'm surprised that unit is largely serviceable, nothing seemed to be overly difficult to repair/replace.

This is how I fixed a slipping rear Haldex clutch on my Golf 7 R. Use VCDS to re calibrate the rear clutch pack. Saved me a lot of money.

It was quite interesting to see the progression from the Mk 4's Haldex to this Haldex-type Not-A-Haldex-because-Borg-Warner-makes-it system. I was curious if the glitter was ferrous or non-ferrous as that might narrow down its origin. Also, I wonder if the pump/screen was clogged with metal debris prior to going into the shop. In any case, it seems like the pump got sad, which made the motor brushes get real spicy, hence the lovely black powder that dumped out of its housing.

My untuned 2016 MK7 Golf R w DSG had a similar failure at 30,000 miles where my car became FWD only (complete with FWD burnouts when launching the car). Unlike your failure, my dealer said they found a bunch of clutch material in the motor filter as the friction material had disintegrated away from the rings prematurely. I was told that the clutch packs weren't fully compatible with the Haldex, erm, "clutch" fluid. The entire rear diff assembly was replaced under warranty. The outgoing unit was "Rev D" found in 2015 and early 2016 DSG models, and the replacement was Rev G or H.

Great video! Cool to see how it all goes together. Fixed my 2016 R with slipping issues at 40k with replacing the pump and new fluid. Seems like the pumps themselves are causing more issues than the clutch units themselves. Service mine every 20k or so with no issues since. Look forward to the DSG breakdown 💪

The lack of serviceable vehicle components and repair parts is shameful. These components were assembled and should be readily disassembled for a rebuild. The right to repair laws that are being considered, which industry is vigorously opposing, may change the repair industry, but it will be slow in coming. Example, Porsche will not rebuild a failed PDK, $20K for a replacement and they will not make parts available if you wanted to rebuild one, so your point on keeping up with the maintenance or shortening the intervals when used in severe conditions is spot on. Only problem is getting owners to actually do it. As usual, great video.

320.000 km & 31 years of use of my Passat Syncro g60 @ 200 ABT hp, no engine repairs, no VCT Syncro malfunctions! Very nice work, congratulations! The Syncro Heresy

I've been considering getting a smaller car but I still want awd. My current car has quattro (torsen) and never really requires any service to that system so it's helpful to see how one of these haldex based systems work and what to expect. Thanks!

A case for 'right to repair'. New clutch pack, motor and fluid looks to be the fix.

Just wanted to help out since I had this issue. Like mentioned (and thank you again HumbleMechanic) it could be the pump, but it can also be the haldex controller which was my problem. Though if your haldex clutch packs are bad you can replace them from Powerzone in Europe. I'm sure they'd carry the clutch packs other places as well. Hope this helps someone.

I can't see why VW/Audi says this isn't a serviceable unit, Its surprisingly simple and uses the same exact clutch style/design as a the DSG transmissions AND that pretty much every wet-clutch driven motorcycle has ever used but just with an electric motor to actuate it!! And the price on the actuation motor is totally absurd too! Awesome stuff as always dude, This was cool as heck to see and it's awesome to see how it works

Being a vw tech this is so interesting to see how the cars we love and work on come apart and work

I'm kind of surprised this isn't serviceable, it's just a lighter version of a wet clutch pack that can be found in most tractors for a whole number of applications. I've had no trouble getting an overhaul kit for the under/over transmission in a 1967 Cockshutt 1750 so it seems kind of ridiculous to me that it's easier to get parts for a 55 year old tractor than it is to even try to get parts to overhaul the AWD on cars that are barely even 15 years old and only seems to need a clutch and pump.

VW Group say that the HALDEX5 system fluid needs changing at 40k miles here in the UK. I tend to do mine at half that mileage (20k). Thanks for showing us the inner working on that unit.

I can smell that motor from my house 😂 Very cool to see this teardown. The mechanical side seems pretty robust.

Great video mate. Nice tear down description. Regards from the UK 🇬🇧

Love these tear down vids. Just a quick request: Are you able to do a feature on the VW/Audi Twin charged 1.4 Engine? It'd be a really cool insight into what was a pretty unique concept for a mainstream drivetrain. Cheers

I definitely deep dive. I'm a (the)fleet mechanic for a tree and Landscape company, theres a lot of vehicles, and equipment. I'm currently rebuilding the fuel injection pump for our 1996 kubota excavator. Lots of yik...but I love it. My golf (that I just berid myself of) was bought when I was still in NC, and, I had a sneaking suspicion the previous owner had an accident involving the ds front.. that became brutally apparent once I moved up to Massachusetts. 3 full suspension rebuilds, swaybar bushings, and it would kick it all out of wack within a year or so. Not to mention the engine mounts got destroyed twice up here.. thats all parts tho..

My mates old Superb 4x4 with the CJX R motor had this with 90k on the clock and was much worse. We re-assembled, changed the filter head on the pump and filled it and sent it. Car went another 40k in his ownership til he sold it. Zero issues.

Thank you for the complete explanation humble mechanic I think you are one of the best channels in KZfaq for VW cars. I just bought a new arteon formotion and you just put the fear of God in me regarding this units. It is really scary to know that a little bit of metal could cause such a complex units to fail.

Ford also used the Haldex system on the mk1 Kuga ( escape in the US) they were known to fail. Always caused by not having the oil changed. The small gauze filter blocks and kills the pump. Ford initially said it wasn’t a service item. However the systems were also used on Volvo cars and Landrover Freelanders. In these applications it was recommended to change the oil and clean the gauze at least every 30k miles. This helped prevent failure. My mk1 Kuga, which I still have suffered a failure at around 40k miles. I replaced the pump with an eBay item. It cost around £230. I have had the oil and filter changed every year since and have had no more problems. Service kits are available on eBay which includes a new filter and a litre of oil for around £60.

Awesome video thank you for that. I'll be servicing my haldex on my S3 next week as its at 30k km's now and your video on that is bloody awesome too.

That clutch pack looks pretty much like a motorcycle clutch. In a motorcycle, the engine, the transmission and the clutch are, in most cases, lubricated by the same oil. Glitter in the oil is normal and I see it at every oil drain.

A couple of Ex VAG mechanics have independently of each other said to me that most of the time on the 5 its the pump that fails and the metal is from inside the pump. One of them said unless you never service it and kick the arse out of it the diffs last for ever. Both said the pumps are complete shite. A quick polish of the clutch plates on this one and a new pump and seals and she’ll be good to go.

It’s a hydrostatic pump with pistons on a ramp like in a lawn tractor transmission. For the pump to make pressure it needs super tight piston to bore clearance. Any wear lowers pump pressure letting the clutches slip. That’s why there is was so much brush carbon in the case. Pump is worn out.

As a mechanic i have never seen a failed Haldex, only clogged filter on the pump. The common failure on these gen 5 rear diffs are the right outer bearing. Have changed so many diffs because of failed bearings. Now i have started to take the diffs apart and change the bearings. I did see vw had a revisioned part after 2018, so maybe that newer diff don't have bearing issues.

I have a 2008 S3 8P. This is the 2nd Haldex failing on my car. The last failure made rear wheels to lockup completely while going at 160km/h on Autobahn. I was on the left lane, had to pull to right in under 100 meters. Otherwise all the cars at the back crash from behind. Was lucky, I was able to save the car from a crash. But it gives no warning on dash, no whining sound of gears, no jerkiness. Everything seems fine, then rear wheels mechanically lock up. If it happened while I was turning at high speed, it would spin or crash at the hands of the most experienced racing driver. Nothing can disengage rear wheels. We had the same lockup in another 2018 model S3 too. I think the design required to be changed. In case of a failure, it shouldn't mechanically lock the wheels. But it happened 2 times on a 8P car, once in a 8V car. I think it may have killed many people, but it would be very hard to explain what happened after a catastrophic car crash, that your rear wheels locked up. And if the driver is living, will tell you this. But it may be hard to prove it in the court. I think Borgwarner needs to take these units back. Change the design with a safe unit. May cost billions though.

Wow! I've always wanted to see how it actually worked. Thanks!

Hopefully the aftermarket will come up with a clutch replacement kit...eventually to keep the Rs on the road, well into the future...

Excellent vid on the the Haldex really great job explaining it also ..Thanks

My wife’s A3 Quattro 40k miles decided to be FWD last winter, im pretty sure this is a big problem, they need to sell a clutch and pump kit

Ewwwww..... that electric motor!!! Any chance that replacing the pump's motor would've been enough to bring that Haldex back to life, considering the underwhelming amount of metal grinds in the oil and clutch components?

manteniment?? video plis!! tanks bro

IM thinking those metal shavings got between the clutches and caused them to drag tripping the computer to sense movement when it should not have any. Not serviceable totally sucks. But a day and the life of newer VWs.

Yeah this doesn't even look that bad? Seems like if the motor were replaced it might work ok again though ideally you'd want to replace the clutchpack...which probably isn't easy to get separately given the "replace the unit" repair protocol. 5th gens do seem a good bit more problematic than the 4th gen units, and interestingly the 4th gen units have a real filter, while the 5th does not. Not sure which engineer(s) decided they don't need a filter in the system, but that wasn't a good move.

I don't like your face. But I respect your knowledge on the euro repair. Half the time I learn something new by listening to you. Great information Always 👍

This video is so informative VW should just link this video to their channel. Thanks man, more please!

My rear diff blew up at 70mph with a violent jolt (one of the tapered roller bearings obliterated itself and cracked the diff open as it did so), very soon after my Haldex oil was changed. Working theory is the specialist garage may have drained the diff accidentally (there's even a TSB about this very thing, so it must not be uncommon), given the tone sounded different after the service. I even took it back to them before it blew saying it sounded wrong, but they sent me on my way.

Great to see the guts on this unit. Thanks for that. With luck, this will be the only time I "get" to see it. Thanks!

really interesting video, ive taken apart a few motorcycle clutches and transmissions before and this is almost exactly the same setup as some of those clutches, nice to fill in the blanks when it comes to car drivetrains

If its a common problem it shocks me that the aftermarket (or dealerships) do not have kits for it. Also if the clutch packs often dislike power why not have a puck set that turns it from sometime all wheel drive to permanent all wheel drive and get rid of the issue?

Maybe if you replace the pump clean everything and the clean the clutches in think it would be fine, would be great to see though

Wouldn't it be better if VW/Audi just change the service interval? And if your car is tuned, does the supplier (APR for example), recommend more frequent service? Good tutorial.

I would buy you a beer or beerzzz if I could. Your vids have helped me billions. 👍

Seems like as long as someone sells replacement clutch packs, it shouldn't be a difficult rebuild. None of the gears or rest of it seemed to have any real wear or damage. Of course if no one sells those discs then your sol. I figure there is probably a minimum thickness the stack needs to be as well so if they are worn to the point that the stack isn't tall enough even cleaning and sanding the steels won't get it running again.

thats why i like the idea of the mk8... goes back to a spool then clutch packs for left and right lol

You always post videos as I’m having similar problems! Great video as always so helpful and yes the curiosity does normally get to me! Haha

It might be considered non-serviceable, but when enough people need a rebuild and it is economical, someone will invent a rebuild kit. The DCT found in the Mitsubishi Evo X was meant to not be serviceable. In early Evo X DCT models, people just had to pay $10,000 for a whole DCT. Mitsubishi called it the TC:SST. This is interesting stuff. I aspire to own and Evo X. Their AWD problem is often having the ACD pump fail. It usually isn't the whole transfer case or diff. I think an ACD pump is $3000. The transfer case of the AWD Ford Taurus doesn't cost nearly as much as the VW Haldex. They just sell brand new ones because of it. The upcoming Toyota Corolla GR is interesting to me. If it can be almost as good as other Toyota Corolla variants, it will provide a lot of fun without costing so much in repair bills, when compared to other fun cars.

Its sad this is not a rebuildable part it seems so straightforward in its assembly eve more so than some automatic transmissions. Is it just that it is such a new design or something else? I know we didn't see the true cause of failure for the particles the pump looks like brush ware but can't see that going into the main area but hmmm. Or was it just you did such a great job showing us the disassembly 👊👊👊👊👊

Ah, the wonders and joy of ‘modern automotive repairs’ Basic Information: Nope, not available Repair Guides: Nope, not available Repair Parts: Nope, not available

Yup ford tech and had a very common ptu failure that was making lots of noise and binding that would usually have windowed the case so I had to rip it apart to see how bad it was. Even though it had a core, I found al.lat nothing left of the pinion gear or ring gear. It smelt sooo bad the fire dept almost got called for a gas leak smell lmao!

Seems typical, the physical parts are still fine but the electrical component fails and/or malfunctions. Wonder if there is a way to just permanently lock the input shaft to the output? Very cool to see the inside of one of these!

Recently ran into this exact issue in our repair shop (albeit our clutch unit had obvious clutch pack pieces in the oil). Unfortunately, I had to get into a heated argument with my colleague (VAG tech of 12 years) who was absolutely convinced that the AWD clutch pack was the exact same as a mechatronic limited slip diff. Needless to say, our relationship has become slightly soured...

Great video. I have a tiguan 4 motion. I hope that I remember to change the both types of oil in due time

Greatest videos on KZfaq! Thank you!!!!

Great job, I just got an Audi S3 8p, this really helps me out

I repair these differentials, replacing all four bearings and four oil seals and thoroughly flush each part as well as the housing, from the inside. And that's not counting the Haldex clutch where there's also one ball bearing and one oil seal. If anyone is interested, please feel free to contact me.

What I saw common too, the module failing with water damage!

I feel like Gen2 and Gen4 Haldex have much lesser problems because they have a separate fluid filter traps all friction discs' debris before it get into the motor.

''it's trash anyway'' Why don't you just clean the metal discs and replace the motor? Or it's probably what you gonna do but not gonna tell anybody and keep this unit for when your car fails. Clever!

Great video, thanks Charles.

Thanks for the video! I am going to be getting a golf R soon! And this helps 🤘

My mom had a 2012 Tiguan she bought new and the Haldex failed around 22000 Km. It was fixed under warranty, after a good fight with the dealer. Dealer in Costa Rica was really a bad one. It has improved a lot in the recent years. I believe it was the pump that failed so the car was basically a FWD instead of a AWD. How she noticed it? When she stopped and start the front wheels will spin. No warning lights or nothing else to let her know something was wrong.

Good vid! It does seem in this case the pump motor is the cause of the failure. I've seen this type of clutch packs in a fishing boat gearbox, where it locked in gear. It was caused by the clutch plates on the input shaft wearing notches in the spline, causing the plates to lock in place so they couldn't disengage not the ideal situation in a boat!

Only question: Why did you keep looking to your right? I've never noticed you do that before in your vids. Something burning on the stove? Haha... Cool vid, as always, Charles!

*me worried af because I just picked up a tuned 2015 S3 with no AWD working 😅☠️ New pump arrives Monday and I hope to goodness that's the issue. Car is less than two weeks ownership 😮

Great video! Really need how to videos on diff / haldex servicing....Audi S5 (B8).

thanks for this video Charles ! I always wondered how this stuff works and now I know .. thanks to you !

How does wheel size effect this unit? On Subaru's, if the front tires are worn and the rear tires are new, the computer interprets this as front axle slippage and will engage the clutch [partially] in order to try to reduce front axle speed. This leads to premature failure of the rear axle clutch pack.....

My guess: the motor is bad, so it wasn't clamping as hard as it should. That caused excessive slipping, thus the unusual wear on the clutch disks. I bet a new motor and clutch would have that back to like-new condition.

Question: If this unit came from from a shop that did some prelim trouble shooting, wouldn't they have drained the fluids themselves? This implies that some of the loose stuff would have been drained out and lost for this tear down. Second: What was the carbon looking stuff poured out of the motor housing? Seems the options are ground up brush material or the motor windings overheated enough to bake the insulation off the windings. Seems like the only way to grind up the brushes would be to have something come loose that allowed the brushes to continue to make contact with the commutator, allowing the motor to keep spinning, until there was no longer enough material to allow sufficient contact.

I have a potential topic for you: VW always had such a good reputation for quality. Something happened around ten years ago, I'm assuming cost cuts to increase margins, and every single time I hear from a VW owner, they have a major malfunction. Engine swap at like 40k km, broken ac, gear box etc. Is this a legit issue and more importantly; why? Mercedes went through something similar around 2004 I think, but they managed to reverse it.

Educational, Charles! Thanks man!✌️

Great explanations

No cat ass trophy 😢 This generation of Haldex has the pump running as long as the engine is running. This causes wear on the brushes, and the dust from the brushes blends with the oil and causes wear on the clutches. The last generation has a different pump design and is actually completely off when 4x4 is not active.

Super interesting! Thanks so much for explaining this so well!

Great video! Of course, as soon as I sell my S3 we get some S3 content. :)

In theory could you weld the clutchpack together and by doing that achieve permament awd

This looked like pump failure. Clutches look fine. Clutches can get really bad before they start having clamping issues.

Great video humble as usual but can’t you point me in the right direction on what’s a good solution to clean the outside of the haldex, bought a used one and it’s full of axel grease and crude lol

Believe it or not I have seen a couple of these diffs assembled together a complete rear end on a subframe with brakes, shocks, springs, axles and stuff a couple of days ago. Kind of mixed bag of emotions to see one of these diffs disassembled due to failure.

Haldex is a subsidiary of BorgWarner. BW is stamped on the case, but it's still Haldex tech.

As a diy, It might be worth a shot to strip it down flush it out and throw a motor on it, curious how long it would last if you just threw a motor on it and a flush

Great content as always

Great explanation! Thanks

Outstanding video, detailed explanation, thank you so much!

I had my rear diff go out on my 19 Sportwagen with 37k. Strong smell of gear oil but no leaks. Rear wheels locked up. They replaced the whole rear. They said the Haldex was fine. About $6k. Under warranty

Hey Charles, Enjoyed the autopsy! Two questions. How much hp/tq can one of those units handle? Is there a high performance aftermarket for that unit? Thanks.

The lack of warning of awd failure in haldex system is not justified. You get warnings for other not-so-important problems, like egr slow opening speed. If the haldex communicates, you are at least prevented about the fwd tracrion only state. And, the other issue, the 3 yrs no miles haldex oil interval. Some people drive a lot, like more than 100k, in 3 yrs. Some drive in harsh conditions (that s the purpose of awd, no?). Also they don't include with the dealers instructions the cleaning of the pump, which manymany people have encountered as compulsory, in some vehicles.

I had to clean off my pump filter and do the adaptation like3 times, and now she takes off like a rocket again

This is the gen 5 Haldex (Borgwarner). I think you dont see a lot of problems on gen4 haldex like on a Golf R MK6 ! Do you think Gen 4 Haldex are better unit ?

I've never owned a VW with the Haldex/similar system. I wonder if there is some kind of modification/bypass to reliably make this system permanent AWD. If there was, I would consider a R32 golf in the future. For now, I'll stick with my B5 S4 Quattro full mechanical drivetrain.

I am entertained. That was really interesting.