Primary pressure regulation valve (page 2 of 5)

1. Low transmission speed
2. Sliding sensor
3. "L" mode actuation lever
4. Connecting lever
5. Support
6. Modulator linkage
7. Spring
8. Roller bearing element
9. Spring
10. Plunger pin
11. Compensating piston
12. Selector cam

If the accelerator pedal is pushed whilst travelling at top speed, the force pushing the transmission ratio control valve towards the left increases. The engine RPM increases from point B to point C on the velocity map (Kick-Down). If, instead, the accelerator pedal pressure is reduced whilst travelling at top speed then the engine RPM decreases, from point D to point E on the same map (Upshift).

1. O/D Overdrive
2. Sliding sensor
3. LOW speed/minimum velocity
4. Modulator linkage
5. Selector cam

When the sliding sensor moves from the "low speed" to the "top speed" position, the reading position on the map moves to the right, corresponding to an increase in the engine RPM. This occurs because the roller bearing element, connected to the sliding sensor via a rod, rotates clockwise and compresses spring (7) so that the distance between the support and the compensating piston increases (L1→L2).

1. Engine speed
2. Throttle valve opening: wide open
3. Throttle valve opening: medium
4. Throttle valve opening: small
5. Top speed (Overdrive)
6. Low vehicle speed
7. Vehicle speed
8. Velocity change characteristic curve map