Shift Sensor 5-speed SMG

The pump motor drives the gear pump, which generates the pressure for the SMG transmission. Both parts together form the hydraulic pump. Without hydraulic pressure, the transmission cannot perform any action – neither change gears, nor operate the clutch. Therefore, the hydraulic pump is the most important component in the system.

In most cases, it is sufficient to replace only the electric motor, as this is a wearing part. The gear pump fails only very rarely. Another advantage is that when only the pump motor is changed, the hydraulic system does not need to be bled afterwards, unless it has been opened.

We sell an original, brand new Magneti Marelli spare part – the same part you would get from BMW.

The pressure accumulator is responsible to store the pressure of the hydraulic system for later access by the actuators. This piston type accumulator has two cells: one cell storing the hydraulic fluid and one cell containing a Nitrogen gas filling which creates the counterpressure. Both cells are separated by a moving piston. Typical symptoms of a faulty pressure accumulator are frequent and short pump cycles. If there is no more preload pressure left in the accumulator, the pump runs every few seconds, which ultimately leads to a consequential damage of the pump motor. Along with the pump motor, a faulty pressure accumulator is one of the most common causes of pressure build-up issues and is one of the few wear parts in the system that should be regularly checked and replaced if necessary.

We offer a brand-new replacement accumulator.