While maintenance negligence (uncleaned screen) is the #1 cause of Haldex pump failures, another physical factor significantly aggravates wear on the system: your tires.
Haldex hates diameter differences
The AWD system works by detecting differences in rotational speed between the front and rear axles. If you fit new tires on the front and keep worn tires on the rear (or if your pressures are totally uneven), the circumferential diameter varies.
The Haldex ECU will interpret this permanent rotation difference as continuous slipping. Result: it will activate the pump and engage the clutches permanently, overheating the system on the motorway. Golden rule for a permanent 4x4: always change all 4 tires at the same time!
Are you affected by this problem?
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