Drive Range, Second Gear. Pontiac Sun Runner - 4WD (Canada) 1997

For 1990-2009 cars

As the vehicle increases speed, the governor allows more drive oil to pass through, and this increased pressure, acting on the end of the 1-2 shift valve, overcomes the 1-2 shift valve spring pressure and allows drive oil to pass through the valve to feed the second clutch oil passages.

Second clutch oil passes through the second clutch orifice control valve, and is metered to the second clutch piston to begin to apply the second clutch, while a portion of the oil is directed to the accumulator. As the upper portion of the accumulator fills with second clutch oil, it overcomes the lesser pressure of 1-2 accumulator oil and spring at the bottom of the accumulator piston, forcing the piston downward. The upper portion of the accumulator is now filled, allowing full oil pressure to the second clutch piston for the final apply. The accumulator, therefore, acts as a reservoir to produce a damping effect for a smooth second clutch apply and the 1-2 shift.

Second clutch oil from the 1-2 shift valve is simultaneously directed to the 2-3 shift valve to be used as the oil source for the 2-3 shift.

#### Summary

The second clutch is on, the band is on, the transmission is in Drive Range - Second Gear.

#### Drive Range, Second Gear

Case Passages