How Haldex (AWD) All Wheel Drive Works ~ Teardown and inspection

Today we look at how VW and Audi Haldex All Wheel Drive (AWD) systems work. How VW and Audi get all wheel drive on some cars. We also teardown a 215,000 mile Haldex and rear differential. This video started out as a limited slip differential install. However I exploded part of the original diff. I lucked out and got a second diff with a Haldex unit.

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disclaimer:
The content of this video is available for informational and educational purposes only. It is not intended to be a substitute for the professional advice of a mechanic who has personally inspected your vehicle, nor does it create a relationship of any kind between the Humble Mechanic and you. Every situation may be different, and the Humble Mechanic does not make any warranties, whether express or implied, as to the accuracy, fitness, or applicability of the information or automotive parts portrayed in this video to any project and makes no guarantee of results. The Humble Mechanic and any sponsors of this video will not be liable for any damages related to personal injury, property damage or loss of any kind that may result from the use or reliance on this video and/or any automotive parts represented in this video. You are using the information and automotive parts portrayed in this video solely at your own risk.

[tomthompson]

The man who never made a mistake, never made anything.

[HumbleMechanic]

Something I am not sure how I forgot to mention. The Haldex and diff fluid are DIFFERENT. If you do the service, be sure to use the proper fluid.

[TimppTV]

Almost 5 years at a VW/Audi dealer as a tech I could never wrap my head around how a Haldex worked. All I needed was this video!
Do newer Haldex units work in a similar way?

[gplusgplus]

DIY detailed install P L E A S E ! ! ! No other video exists of this job ( I have a spare haldex waiting for this). Also, I hear you need to also put an LSD at the front gearbox/transfer case; the front LSD has more pronounced result than the rear LSD (obviously better to do both).

[scottibass]

Amazing how much pressure a snap ring can take!

[andrewgonyou]

never been super big on euro stuff, but I have to admit the threaded holes to press the parts apart is pretty genius

[bradcarpenter]

I know this comment is months after upload and likely to never be seen by anyone lol, but how does this vid only have 90k views?! This is incredible top notch gearhead content and about as professional quality as you can get from being on YT. This channel deserves way more views!

Honestly I think the problem these days are that the are so many "car related" or mechanic related channels that makes it difficult for YT algorithms to properly promote the better, underrated channels. For that, I did my part and hit the like button!

[stephenprice]

Super cool to see this video. That was a bit of an "oops" moment, but at least you managed to get another.
I remember having to press half shafts for a Jaguar XF out so I could replace bearings. No forgotten snap rings, just seized tapers. 40T press failed to shift them. Ended up taking them to an heavy goods service centre who failed to press them out with & 15OT press. They had to take them round to the big boy toy and that registered 265T before the shafts finally broke taper. The bang was super loud.

[nei]

This system is amazing. Its actually smart enough to shut itself off when the unit is low on oil. I had a Audi TT quattro that had a non working rear diff. I just changed the filter and oil and it came back to life.

[emilianofloridia]

Try with dry ice blasting. It's not cheap but the best result, and good content for the channel. Greetings from Argentina!

[AdamShaiken]

Heated pressure washer with a citrus based solvent for cleaning the case.

[europerformance]

Sodablasting is a great way to clean it up without damaging anything

[Honda-tegq]

If the haldex clutch plates were replaced with solid drive plates, wouldn't that cause the front and rear axle to bind? Your enthusiasm and energy is admirable.
Thanks for sharing your knowledge.

[jeremys.]

A testament to the strength of snap rings everywhere

[SplicesAndCelluloid]

Past Charles: "I'm nervous about this part"
Little does he know...

[miketeeveedub]

Great video Charles! I like how the Haldex is basically an eletronically-controlled dirt bike wet-clutch assembly mated to a differential housing. I also like how the actual differential is separated from the ring/pinion gear drive via an input shaft. MUCH easier to set up then lets say a LSD on a ford 9" or a GM 10/12 bolt, but a bit more difficult to get to those same internals.

The one bit of advice I'd like to add is: the secret to long Haldex diff/clutch life is to change the Haldex and diff gear fluid on a regular basis. Every 20 or 30K. The Haldex fluid isn't cheap, but it's cheaper then replacing the ECM, pump and pressure switch. Ask me how I know that! 😢 💸💸💸

Love your content bro! Cheers!

[tonylopes]

Hello Charles, first of all I want to thank you for all the awesome things you show us. I also like to add that your not an idiot for what you did, its all in a days work, I do that all the time that's how we learn sometimes. I hope I learn from my mistakes, anyway awesome job. Those who do will eventually brake something and learn, those who don't will never learn anything lol.

[herrkulor]

I just love those 3 finger pullers. Things come of with such ease when the forces align perfectly. Instead of hammering and random

[oetic]

You're always the man to watch. Love to watch these lengthy vids is really informative and relaxing.

[darrelsmith]

Would love to see a full assembly video. Always love to see how you explain things and how you show the methodical process you take to restore things