Does anyone know much about them? My ESP light has been on for months and that is the problem. How many people have changed the Haldex filter and oil. Apparently supposed to be done every 4 years or 40k
tommyd_tt
Outline
The Haldex unit is an electro mechanical component used to put engine power to the rear wheels to engage 4 wheel drive for the quatro models of the TT.
Haldex is actually a company, manufacturing amounst other things the Haldex limited slip coupling used in vehicles with automatic all wheel drive systems to engage and disengage a secondary axle when needed.
Among European car fans "Haldex" refers to the aforementioned differential system: its most prominent use is in all transverse engine 4x4 models of the VAG group (Audi A3 and TT, Volkswagen Golf and Passat), making them non-permanent 4x4s, unlike longitudinal engine models (Audi A4, A6, A8) which use a Torsen-like differential. However, its short reaction time (only a seventh of a wheel spin) amply makes up for its non-permanent AWD (like Torsen) setup.
Also noteworthy is that purists despise the fact that "low end" Audis equipped with the "Haldex system" bear the same name (quattro) as their "greater" brethren using the Torsen differential: true, the original Audi Quattro coupe did use a Torsen differential - but then again, it had a longitudinal engine.
[edit]
Known Issues
Not known to fail very often, however most TT owners would prefer a more active 4 wheel drive system so if it does fail then it is recommended to replace with the "Performance Haldex Controller". This provides a more agressive, faster, predictive activation of the 4 wheel drive system. See more below.
[edit]
OEM Part Number
TBD
[edit]
How to disable the Haldex Controller
Pull the handbarke on one notch, that is it no disabled, useful for when there is only a two wheel rolling road available.
[edit]
How to change the Haldex Controller
Courtesy of WAK
A great how to can be found here.
[edit]
How to change the Haldex Oil and Filter
Courtesy of John-H
A great how to can be found here.
Courtesy of WAK
A great how to can be found here and here.
[edit]
Source of alternative replacement parts
An uprated haldex controller is available from a number of TT specialists, more info Haldex
The Haldex Performance Part will greatly improve the performance and handling of the Audi TT Quattro, Audi S3 or Volkswagen R32. The kit consists of a new electronically controlled valve body, gaskets, necessary hardware and installation instructions. By re-tuning the vehicle's AWD system, power is more aggressively directed to the rear wheels under a wide variety of driving conditions. The Haldex ECU continuously monitors throttle input and other vehicle sensors and transfers torque more quickly to the rear wheels when driving aggressively. In fact, how quickly the torque is transferred is a direct function of how fast the driver pushes the throttle pedal - The Haldex unit will actually anticipate and prepare for torque transfer before actual torque is delivered from the engine to the driveline. The result is more neutral handling characteristics and better off the line acceleration. This system does not interfere with ABS or Traction Control Systems.
The Haldex unit is an electro mechanical component used to put engine power to the rear wheels to engage 4 wheel drive for the quatro models of the TT.
Haldex is actually a company, manufacturing amounst other things the Haldex limited slip coupling used in vehicles with automatic all wheel drive systems to engage and disengage a secondary axle when needed.
Among European car fans "Haldex" refers to the aforementioned differential system: its most prominent use is in all transverse engine 4x4 models of the VAG group (Audi A3 and TT, Volkswagen Golf and Passat), making them non-permanent 4x4s, unlike longitudinal engine models (Audi A4, A6, A8) which use a Torsen-like differential. However, its short reaction time (only a seventh of a wheel spin) amply makes up for its non-permanent AWD (like Torsen) setup.
Also noteworthy is that purists despise the fact that "low end" Audis equipped with the "Haldex system" bear the same name (quattro) as their "greater" brethren using the Torsen differential: true, the original Audi Quattro coupe did use a Torsen differential - but then again, it had a longitudinal engine.
[edit]
Known Issues
Not known to fail very often, however most TT owners would prefer a more active 4 wheel drive system so if it does fail then it is recommended to replace with the "Performance Haldex Controller". This provides a more agressive, faster, predictive activation of the 4 wheel drive system. See more below.
[edit]
OEM Part Number
TBD
[edit]
How to disable the Haldex Controller
Pull the handbarke on one notch, that is it no disabled, useful for when there is only a two wheel rolling road available.
[edit]
How to change the Haldex Controller
Courtesy of WAK
A great how to can be found here.
[edit]
How to change the Haldex Oil and Filter
Courtesy of John-H
A great how to can be found here.
Courtesy of WAK
A great how to can be found here and here.
[edit]
Source of alternative replacement parts
An uprated haldex controller is available from a number of TT specialists, more info Haldex
The Haldex Performance Part will greatly improve the performance and handling of the Audi TT Quattro, Audi S3 or Volkswagen R32. The kit consists of a new electronically controlled valve body, gaskets, necessary hardware and installation instructions. By re-tuning the vehicle's AWD system, power is more aggressively directed to the rear wheels under a wide variety of driving conditions. The Haldex ECU continuously monitors throttle input and other vehicle sensors and transfers torque more quickly to the rear wheels when driving aggressively. In fact, how quickly the torque is transferred is a direct function of how fast the driver pushes the throttle pedal - The Haldex unit will actually anticipate and prepare for torque transfer before actual torque is delivered from the engine to the driveline. The result is more neutral handling characteristics and better off the line acceleration. This system does not interfere with ABS or Traction Control Systems.
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