D-4 - Second Gear

With 4L60 (700-R4) Transmissions - 4WD Shown, 2WD Similar:

D-4 - SECOND GEAR

2-4 BAND - APPLIED
FORWARD SPRAG CLUTCH - HOLDING
FORWARD CLUTCH - APPLIED

As both vehicle speed and governor pressure increase, the force of the governor oil acting on the 1-2 shift valve overcomes the pressure of Modulated Throttle Valve (M.T.V.) up oil and the force of the 1-2 throttle valve spring. This allows the 1-2 shift valve to open and Drive 4 (D4) oil to enter the second (2nd) oil passage. This oil is called second (2nd) oil. Second oil from the 1-2 shift valve is directed to the following:

1. 1-2 Shift Checkball (8)
2. 2-4 Servo
3. 1-2 Accumulator Piston
4. Converter Clutch Shift Valve
5. 3-4 Relay Valve

BASIC CONTROL

Second oil from the 1-2 shift valve will seat the 1-2 shift checkball (8) forcing 2nd oil through an orifice. Second oil is then directed to the 2-4 servo to apply the 2-4 band. At the same time, 2nd oil moves the 1-2 accumulator piston against accumulator pressure and the accumulator spring to maintain a controlled build-up of pressure on the servo during the 1-2 shift for a smooth band apply. 2nd oil at the converter clutch shift valve and the 3-4 relay valve is available for use in other ranges.

Second oil is rerouted into converter clutch signal oil at the bore plugs used in place of the converter clutch shift valve. Converter signal oil exhausts at this solenoid until a signal is received from the vehicles E.C.M.

SUMMARY

The converter clutch is released, the 2-4 band is applied, the forward clutch is applied, and the forward sprag clutch is holding; the transmission is in Drive (D) Range - Second Gear.