ECVT Loss of Line Pressure

When diagnosing an ECVT transmission that has a severe slipping condition, check to see if you have line pressure. If there is no pressure, there are a couple of likely causes. One, with which you may already be familiar, could be a severely cracked secondary pulley. Another, which you may not be familiar with, could be an oil pump drive shaft that has disengaged from the oil pump impeller shaft.

The engine end of the oil pump drive shaft has a clip on it to limit how far it can penetrate the flex-plate. This clip may become damaged during installation after a repair (especially if the transmission was removed without removing the engine). Also, if there is excessive wear in the splines of the driveshaft and/or flex-plate, the play in the spline area may break the clip. In either case, without the clip, the oil pump drive shaft can walk far enough into the flex-plate to disengage from the oil pump impeller shaft, causing the pump to stop.

During your inspection of components, look for a missing clip on the oil pump drive shaft and check the fit of the shaft into the flex-plate. If there is excessive play, replace both the drive shaft and the flex-plate.

Note:
Never try to withdraw the oil pump drive shaft out through the oil pump end of the transmission. This will damage a seal inside the transmission input shaft.