Symptom: 2009 3.0-liter BMW X3, a year in September with gearbox damage been overhauled at a repair workshop, every morning D-speed start crawling slowly appeared four months later, in particular from the underground garage when traveling upward momentum Is very poor, even to slip backwards.
DiagnosIs: DiagnosIs of the gearbox computer trouble codes, the transmIssion speed start determination Is 1 not into safe mode.
detecting the oil level, oil quality, oil pressure, no exception. Through the work flow chart gearbox initially suspected as the forward clutch problems may arIse.
further communication with the owners and queries when the last maintenance bill of materials and old parts found inside the gearbox rubber pIston Is not replaced. The main function of the Automatic transmIssion hydraulic pressure of the pIston Is converted into a linear motion. I.e. by the pIston
pushing drive multiple dIsc clutch engagement, to form a desired gear position. The pIston Is generally divided into two types, one Is made of metal castings and machined plates rubber ring, rubber ring for sealing fitted on the metal casting. Another Is an integrated pIston (commonly known as plastic pIston), i.e. the metal frame through a rubber mold Is directly bonded.
of the pIston can be integrated into four categories:
More driving pIston,
a balance pIston (or compensation pIston), the servo pIston and accumulator
of the pIston means. Integrated drive pIston to seal lip usually through effect.
However, plastic pIston in the operating state of the reciprocating motion of the long-term aging, fatigue (especially the lips closed) phenomenon Is inevitable.
a lot of Cars with mileage over 150,000 kilometers, plastic pIston gearbox overhaul Is specified as components must be replaced.
by shifting dIsmantlingBox, found inside the transmIssion Is basically consIstent with the above rubber pIston.
Replace the relevant parts, testing, fault dIsappears.