583Fluid flow in drive range first gear

Both main pressure regulating valve and throttle pressure valve operate as for neutral and park.

With the manual selector valve in D, line pressure is directed to the 1-2 shift valve, 2-3 shift valve and to the forward clutch which it engages.

The shift valve is subjected to governor pressure at one end which opposes the spring tension and throttle pressure at the opposite end. As the car speed increases governor pressure will overcome throttle pressure causing a 1-2 upshift to take place.

Throughout this period a reduced line pressure reacts against the left hand end of the main pressure regulating valve. The valve movement then allows more oil to pass to the torque converter, thereby causing a reduction in line pressure to occur.

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

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