In general, a valve body of the automatic transmission(AT) is controlled by the clutch, the brake and
lubricating oil flow in a hydraulic system and lubricant flow for each valve can be adjusted independently. To
increase the lifetime of AT, the lubrication flow rate in a valve body for a 6 speed AT based parallel hybrid
electric vehicle must be provided with proper oil distribution and control. In this study, we carried out several
experiments without the inner parts of AT and with a AT assembly. The variation of the flow rate on oil
temperature and pressure between an oil supply port and the outlets of the lubrication port was evaluated and
analyzed. In the case of AT without the inner parts, it was evident that as the oil required for an operation of
the clutch and brake was discharged from the outlet port, the flow rate from each lubrication port is
decreased. However, the flow rate of the AT assembly was slightly increased. In addition, the lubrication flow
rate was increased with increasing the oil temperature, and also it was reduced with increasing the oil
pressure. Details of the resulting data are discussed.