Full Throttle Detent Downshift. Chevrolet Beretta 1996

For 1990-2009 cars

For a view of the oil flow diagrams, refer to the 1996 TURM Manual.

While you are operating the vehicle at speeds below approximately 105 km/h (65 mph), you can achieve a forced or detent 3-2 downshift by depressing the accelerator pedal fully. This action will position the throttle valve (TV) plunger, allowing the shift TV oil to enter the detent passage. This oil, called Detent oil, is then routed to the following components:

• | The 2-3 throttle valve

• | The 1-2 throttle valve

• | The RNDI and detent checkball

Detent oil from the TV plunger flows to the 2-3 throttle valve. Detent and part throttle (PT) oil pressure combines with the 2-3 spring force in order to close the 2-3 shift valve against governor oil. This allows direct clutch oil through two orifices to exhaust at the 2-3 shift valve.

At high vehicle speeds, above approximately 80 km/h (50 mph), governor oil acts on the 3-2 control valve and closes the 3-2 valve. Now the direct clutch accumulator oil exhausts from the intermediate servo and seats the direct clutch accumulator checkball. The oil flows through another orifice controlling the intermediate band apply for a smooth 3-2 shift at high speed.

A detent 2-1 downshift can be accomplished at speeds below approximately 48 km/h (30 mph), because detent oil pressure and the 1-2 spring force act on the 1-2 throttle valve in order to close the 1-2 shift valve. This shifts the transmission into First Gear.

Detent oil acts on the RNDI and detent checkball, but the oil will not unseat the checkball because RNDI oil is at a higher pressure.