# DIY - Replace Haldex Gen2 Filter and Fluid Audi TT MK2



## TT4LEE (Mar 8, 2015)

There are several versions of the Haldex unit and some DIYs on the Golf but when I wanted to refresh my 2008 Audi TT 3.2 Mk2 with the Gen2 Haldex - I could not find a model specific guide.

My car manual says to change the Haldex fluid at 55,000 km (then 115,000km, then 170,000km). There doesn't seem to be a recommendation for how often to replace the filter - I opted to do the filter and fluid at 85,000 km - for me half way through the vehicle lifespan and likely the last time I'll replace the filter). I bought the car at 80,000 km and assume it never had either replaced. From my experience the fluid change was easy and inexpensive; I leave it to you to decide whether to replace the filter.

This job can be done in an hour or less. An oil-only change would take half the time.

Here's my process,

*You'll need *


A filter if you want to change it. Cost is high at about $80 for the Gen2 Haldex (Mfg Part #02D598574)
Haldex fluid ( I used 750 ml from a 850 ml bottle) cost $35 (Mfg Part #G055175A2)
Might as well replace the fill and drain bolts so they won't leak $11 total
 - Fill Bolt Mfg Part # N-902-818-02 size is M10x1x10mm
- Drain Bolt Mfg Part # N-910-827-01 size is M10x1.5x30mm

24 mm socket and wrench (for Haldex filter)
5 and 8 mm hex keys (fill and drain plugs)
Transfer pump (several ways to do this)
1/8" to barb brass fitting for refilling Haldex

*Get Started*

You only need to lift the rear of the car, so a set of ramps under the rear wheels works very well. You need the car to be level (front to back) so that when you refill the Haldex fluid you get the level right.

This guide is for the Haldex Gen2 which has the code 0AV stamped on the housing (second string of code on my housing). Other versions use different filters (Gen 4 Haldex has the code 0BR, or 0BS/0AY, or 0BY). You can see the code on the next photo.










It is always a good idea to check that the fill bolt can be removed before removing the drain bolt or filter, so that you don't end up with a drained system with no way to fill it&#8230;.

I used a bit of liquid wrench to ensure the bolt would move without being stripped. I marked the Haldex Drain (HF) 8mm hex, and Haldex Fill (HF) 5 mm hex in black marker.










You can remove the 5 mm filler bolt at this point.

I then drained the Haldex removing the 8 mm drain bolt. About 750 ml will flow out, catch this and dispose of it properly. My fluid was pretty dark but with no solids, the new fluid is very light yellow.










Now to remove the Haldex filter. I found that it was a very tight fit getting at the filter which for the Gen 2 needs a 24 mm socket. I used a narrow ratchet and an adapter to get clearance between the filter housing and the other bits&#8230;



















Here is the filter housing with the washer and the old filter plus a new filter. My filter at 85,000 km was pretty black.

Note here that the new one looks wrong, that is because the end cap can be removed from the filter cylinder and in the case of the new one, it is on the wrong end  if so pull it off and put it on so the spring is at the opposite end. When you reinstall the filter the spring end goes in first. My filter "kit" came with a new filter housing bolt. Wrench it back in.










Now reinstall the drain plug. Then refill the Haldex with Haldex Fluid. My bottle came with 850 ml and I used about 750 ml. I used a simple $10 fluid transfer pump which came with a short hose.










I screwed a 1/8" brass pipe about one turn into the fill hole (the threads are not identical so just screw in very lightly - this enables filling with no fluid escaping). Then push the plastic hose onto the brass pipe barb.










Fill the Haldex with about 800 ml of Haldex fluid, and then let the excess drain out. If none drains out, you need to add more as that is your level control.










Reinstall the fill plug. Lower the car and you're done.


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## rajanm1 (Feb 1, 2014)

Great writeup!


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## JentoneTTS (Apr 28, 2016)

Splendid, thank you, mine is a 2012, so I need to see which filter I have.


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## fuzzylogic (Jun 8, 2016)

Cant thank you enough man. Awesome write up. Gold stars to you. I just did mine on my 2008 TT and this was on the spot. I even managed to get a brass nipple that looked exactly like yours haha. Surprisingly my gen2 was quite under oiled when I measured the old oil coming out. I'm quite glad I did this as my car obviously really needed it. Thanks again


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## legend139 (May 9, 2014)

Just out of curiosity would you recon there would be any need to do a flush prior to filling up with the correct spec oil.. Or would it just be a waste..

Great write up btw!

Cheers
Connor

Sent from my iPhone using Tapatalk


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## TT4LEE (Mar 8, 2015)

I don't think there is any reason to flush it, you get a pretty complete drain just pulling the plug, and the fluid is filtered so little more than a refresh of fluid is occurring...


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## SwissJetPilot (Apr 27, 2014)

Some additional comments -

1.) Both the Gen 2 and Gen 4 Haldex pumps have a plastic filter (strainer) built into the end of the pump. If you're going to the trouble of servicing your own Haldex, it's probably worth removing the pump and cleaning the filter while you're there. You'll have to disconnect the plug at the Control Module and free the three cable harness clips.

2.) While the barbed brass fitting mentioned in this write up does work, there's a VAG specific part that's purpose made for this procedure called; _Charging Device F/Haldex 2 Coup. -VAS 6291-_. You can find a reference for it in the Workshop manual Rear Final Drive (linked below) on page 123. If a VAG shop doesn't have it, you can probably pick one up from eBay or Amazon.

*TORQUE VALUES - *

Oil filter cover ........................ 35-Nm
Drain bolt .............................. 30-Nm
Fill bolt .................................. 15-Nm
Oil pump retaining bolts (x2) ..... 6-Nm

*WORKSHOP MANUAL -*

Here's the workshop manual for further information and specific instructions -
View attachment D3E80023195 - Rear Final Drive.pdf

*NOTE - *

If this DIY is beyond something you want to tackle, be sure to discuss the filter replacement and pump strainer cleaning with your Service Tech. Because Audi calls it a "non-servicable lifetime filter" it typically gets over looked. You can read more about why in this post - https://www.ttforum.co.uk/forum/viewtop ... &t=1850793

















































_Filter and pump images courtesy of Haldex Parts and ECU Repairs by Auto Fault Finder Ltd – Haldex Mail order parts and ECU repair services_
.


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## ryguy (Sep 21, 2020)

This is a really old post, but I am looking to build an inexpensive VAS6291 tool. Does this fitting look like it meets the specs for the Haldex end? For the record, I have a 2012 Audi TT Quattro Coupe and a 2013 VW Tiguan 4Motion. Amazon.com: Metric Thread M10 M10X1 Male to Barb 3/8” 10mm Brass Air Fuel Gas Oil Boat (2 Units) : Automotive


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## FNChaos (Nov 30, 2016)

ryguy said:


> Does this fitting look like it meets the specs for the Haldex end?


If the adapter is truly M10x1 then it should screw into your fill port (picture looks like coarser thread but it might just be a generic pic).

Assuming you are building a simple gravity drip set-up?


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## ryguy (Sep 21, 2020)

FNChaos said:


> If the adapter is truly M10x1 then it should screw into your fill port (picture looks like coarser thread but it might just be a generic pic).
> 
> Assuming you are building a simple gravity drip set-up?


Yes, that is exactly the plan.


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