All-Wheel Drive Coupling Haldex Generation 1 (GEN 1)
2001 Audi S3 – GEN 1 Haldex AWD Coupling
About the Haldex GEN 1 All-Wheel Drive Coupling
In 1998 VAG introduced the first-generation all-wheel drive Haldex coupling, this meant they could turn a transverse mounted front wheel drive vehicles into all-wheel drive.
The MK4 Golf 4Motion was the first vehicle to be fitted with GEN 1 Haldex, this early AWD set up was mainly a reactive system. In normal driving conditions the torque distribution is 90/10 for front to rear. The coupling engages when wheelspin is detected. If the traction system alerts the vehicles ECU that it has a front wheel spinning, the Haldex clutch will then lock, and torque is evenly distributed 50/50 between both front and rear axles.
The traction system reaction is almost immediate, and it takes just ¼ of a wheel spinning to activate Haldex Coupling for the vehicles all-wheel drive feature.
In 2002 VW released the Edition 25 Golf GTI which represents one of the most sought-after vehicles to this day and is a collector’s item. This led the group to fitting the All-Wheel Driving Coupling to the performance R line Golfs e.g., the MK4 R32 up to the present day MK8 Golf R. The later generations of the Haldex system are a lot more sophisticated. We have detailed the differences in the about section of each Generation.
Service Interval for Vehicles Fitted with a GEN 1 Haldex Coupling
|All-Wheel Drive Coupling Haldex Generation 1 (GEN1)||1st Oil Service||Oil & Filter|
|Audi A3 S3 8L Quattro 1998 - 2003||20,000 Miles||40,000 Miles|
|Audi TT 8N Quattro 1998 – 2006|
|VW Bora 2.8 V6 4motion 1998 – 2004|
|VW Golf 1J Mk4 R32 4Motion 1998 – 2004|
|VW Sharan 7M Phase 1 Mk1 1998 – 2007|
|VW New Beetle RSi 1998 – 2003|
|Skoda Octavia 1U 4×4 Mk1 1998 – 2004|
|Seat Leon 1M Mk1 Cupra4 1998 – 2005|
|Seat Alhambra 7M 1998 – 2007|
How to perform a GEN 1 Haldex Coupling Service
Required Parts for Servicing the Haldex GEN 1:
- OEM Part Number: G 052 175 A1 - High Performance Oil for Haldex Coupling (275ml) x 1
- OEM Part Number:02 D52 555 8A - Gen1 Haldex Filter
- OEM Part Number: 02 D52 572 9 – Drain Bolt
Haldex GEN 1 Servicing Tools
- Angled ring spanner 46 mm – specific tool for the Gen1 Haldex Filter Housing (See image below)
- 5mm Hex or 5mm Allen Key – Drain/Fill Plug
- 3/8 Torque Wrench
- Caulking Gun – to push oil into the coupling
- Diagnostic Tool – VCDS / VAGCOM / ODIS & VAS TOOL / Other tool Capable of reading the oil temperature in the Haldex Coupling
Diagnostic Guide for Checking Oil Temperature for GEN 1 Haldex:
Using your diagnostic machine, you can check the Temperature of the Oil in the Haldex Coupling:
- Connect Vehicle Diagnostic Testing Machine
- Select - Running gear Group 01; 40…49
- Select - Four-wheel drive with Haldex coupling
- Select - 01 - Self-diagnosis-capable system
- Select - Four-wheel drive Haldex
- Select - Electrical components
- Select - Oil temperature
- The oil temperature must be between 20 and 40 °C before you empty the oil from the Haldex Coupling
Top Tip – the oil will be close to the right temperate if the vehicle has been driven/idling before you start the process
Procedure for Emptying the Haldex GEN 1 Coupling of Oil:
Once you have checked the oil is at the correct temperature with your diagnostic tool, you can now start the process of emptying the oil from the Haldex Coupling.
- Make sure the vehicle is level and safely placed on your ramp
- Remove Inspection Port bolt (5mm Hex/Allen)
- Check the current oil level – if the level is a lot lower than the 3mm below the edge, make sure all diagnostic checks have been performed and ask customer if the vehicle has had any symptoms of poor performance relating the Haldex System
- Place Oil catch under the oil drain plug (5mm Hex/Allen) and remove
- Using the Angled ring spanner 46 mm Crack loose the Filter Housing, once loose use fingers to remove and angle filter around to remove fully – Filter Location: hidden by the sub-frame on righthand side of vehicle near front mounting bracket.
- Allow the entire contents to empty (Dispose any oil legally and be environmentally friendly)
Filling the Haldex GEN 1 Coupling with Oil:
- Replace Filter - 35nm torque, however as a guide make sure you feel the filter seal and ensure there is no gap with your fingers – Remember to lube the new o-ring with the clean Haldex Oil, ensuring a good seal is made when you replace filter cap
- Method 1 - Use Caulking gun and vertically fill High Performance Haldex Oil (PN: G 052 175 A1) into fill /drain hole – make sure the adapted nozzle fits snug in the hole to stop it leaking oil
- Method 2 - Alternatively you can empty the Oil into a container and syringe through the inspection hole until you reach to correct fill level - 15nm torque on 5mm Hex/allen – this can save wastage and is the preferred method of the later generation Haldex Systems.
- Pump / fill entire contents (250ml) of the oil into Haldex coupling.
- When filling through the Drain/Fill hole, be ready to replace the plug immediately after filling (torque setting 15nm the 5mm Hex/Allen) (if you lose too much oil then you will need additional oil to reach the correct fill level)
- Check fluid level in Haldex coupling – (Fluid level is correct when Haldex coupling is filled to lower edge, or at least to within 3 mm of lower edge visible from the inspection hole.
Common Faults for a GEN 1 Haldex Coupling
The wiring on the GEN 1 haldex coupling seem susceptible to becoming brittle and where you find electrical or open circuit faults on the AWD (22) section in your diagnostic menu, it is worth checking the wiring and earth points.
How to test if the Haldex Coupling is working
Once you have scanned the vehicles AWD for any fault codes you are now able to test if the coupling is engaging when the vehicle senses the front wheels slip.
To test the function of the GEN 5 Haldex Coupling follow the below instructions:
Testing the physical function of the Haldex will require either a rolling road or brake roller tester.
- With the front wheel on the rollers engage 1stgear / drive
- Rev the engine in gear until you 1500 rpm
- If the rear axle does not engage at this point and try to push the vehicle forwards then the Haldex Coupling is defective and further diagnosis will be required
Changing the GEN 1 Haldex pump
This procedure is a little more involved than replacing the pump like it is on the later generations of the Haldex Coupling. To gain access to remove the pump you will first need to unbolt the rear of the propshaft. This process should be undertaken on a 2-post ramp and the vehicle will need to be stable as stress will need to be applied to the gearbox, engine, and rear differential to remove the propshaft. For those reading who wish to purchase a pump and proceed with fitting it yourself please see our guide below.
Note: Before starting clearly mark the positions on each part. When you come to reinstall, the parts be sure the positions match up from when you removed them. This will maintain the factory balance applied when the vehicle was built. DO NOT FLEX THE PROPSHAFT WHILE REMOVING/INSTALLING
- Unbolt the flexible coupling attached to the front propshaft (12pt Flange Bolt – 60nm)
- Dependant on which vehicle you are working on you may need to remove the centre section from the exhaust
- Remove the dogbone mount from the subframe
- Remove the Front and middle heatshields
- Unbolt the front propshaft from the rear propshaft
- Using a pry bar gently press the engine and gear box forward
- Place gearbox jack under the rear propshaft to hold in place (DO NOT FLEX EITHER PROPSHAFT)
- Remove the front propshaft off the centre pin carefully
- You should now be able to remove the front propshaft
- Unbolt the rear propshaft and flexible coupling vibration dampener from the rear final drive (MAKE SURE YOU HAVE MARKED ORIGINAL PLACING)
- You can now remove the rear propshaft off the centre pin, giving you access to the Haldex Pump. Three 12pt Flange Bolts (60nm)
- Remove the two 10mm (6nm) sockets and unplug the Haldex Pump from the Haldex Controller and remove
- Once you have installed the new Pump, you can now replace the above parts in the reverse order with the correct nm for each bolt listed above
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