D-4 - Overdrive

Drive Range - Overdrive:

D-4 - OVERDRIVE

CONVERTER CLUTCH - APPLIED
FOURTH CLUTCH - APPLIED
DIRECT CLUTCH - APPLIED
FORWARD CLUTCH - APPLIED

As both vehicle speed and governor pressure increase, the force of governor oil acting on the 3-4 shift valve overcomes the force of the 3-4 Throttle Valve (T.V.) spring and Modulated Throttle Valve (M.T.V.) up oil. This allows the 3-4 shift valve to open and RND4 oil enters the fourth clutch passage.

Fourth clutch oil from the 3-4 shift valve is directed to the following:
1. Fourth Clutch Apply Piston
2. 3-4 Accumulator Piston

BASIC CONTROL

Fourth oil from the 3-4 shift valve is directed to the fourth clutch piston to apply the fourth clutch. At the same time, fourth clutch oil moves the 3-4 accumulator piston against accumulator pressure and the accumulator spring to maintain a controlled build-up of pressure on the fourth clutch during the 3-4 shift, for a smooth 3-4 shift.

SUMMARY

The converter clutch, fourth clutch, direct clutch, and forward clutch are applied; the transmission is in Drive (D) Range - Overdrive.

The converter clutch may or may not be applied, depending on solenoid operation.