Genuine 1996 BMW Z3 Transmission Assembly

1996 BMW Z3 Transmission Assembly Parts Questions & Experts Answers

• Q: What are the functions and components of the Transmission Assembly on the 1996 BMW Z3?

  A: The automatic transmission allows engine torque and power to be transmitted to the rear wheels within a narrow range of engine operating speeds. It uses a light fluid as the medium for the transmission of power and also works in the operation of various hydraulic control circuits and as a lubricant. The torque converter replaces the conventional clutch and has three functions: allowing the engine to idle with the vehicle at a standstill, allowing smooth shifting between ranges without closing the throttle, and multiplying engine torque as vehicle speed drops and throttle opening is increased. The torque converter consists of a metal case with three sets of blades: the torus or pump, the turbine, and the stator. Under low speed acceleration, the fluid flows through the torus and turbine, picking up speed and energy, and is redirected by the stator to allow the torus to turn faster than the turbine, resulting in higher engine power output and torque multiplication. A planetary gearbox is used to carry the power output of the turbine to the driveshaft, providing various reduction ratios. Servos and accumulators are used to engage the bands and clutches, with the servos being hydraulic pistons and cylinders and the accumulators cushioning their engagement. The hydraulic control system uses pressure from the main transmission oil pump, channeled through shift valves, to operate the servos. Governor pressure and modulator pressure, affected by vehicle speed and throttle position, respectively, control the operation of the shift valves and delay upshift points to optimize engine power output. An auxiliary circuit is used for downshifting, actuated by various means such as the throttle linkage or a solenoid. The transmission modulator also governs the line pressure to match the torque output of the engine for proper actuation of the clutches and bands.