A500 Power Flow

FIGURE 2:

In third gear, the power flow comes off the intermediate shaft simultaneously into the planet carrier and the overrunning clutch. From the carrier, the power flows into the sun gear, then to the inner sliding hub splines. The direct clutch holds the sliding hub to the direct clutch drum under spring pressure. The drum engages directly with the annulus for a one-to-one ratio. The annulus is splined directly to the output shaft (Figure 2).

FIGURE 3:

The overrunning clutch carries the power flow during the shift into fourth gear. When the SMEC energizes the overdrive solenoid, the third gear line pressure starts to move the overdrive piston rearward. The piston pushes the sliding hub and begins to compress the direct clutch spring. Now, with spring pressure relieved, the direct clutch is disengaged. Power flows only through the overrunning clutch (Figure 3).

FIGURE 4:

As the sliding hub is forced further rearward, the overdrive clutch engages, stopping the sliding hub and sun gear and hold them to the overdrive case. As power enters the planet carrier, its gears move around the stationary sun gear and the engine can now turn less for one revolution of the output shaft (Figure 4).
The lockup torque converter is also controlled by the SMEC. Once in fourth gear, the SMEC signals the lockup solenoid to close where the existing pressure builds to move the lockup valve. The lockup valve directs pressure to the torque converter where the turbine is clamped to the spinning torque converter housing. This eliminates any slipping normally attributed to automatic transmissions.
The lockup timing valve releases the torque converter to normal operation prior to the 4-3 downshift.

Additional A-500 Information

^ All closed throttle 3-4 upshifts will occur at 25-28 mph, regardless of axle ratio.

^ All closed throttle 4-3 downshifts will occur at 25 mph, regardless of axle ratio.

^ No 3-4 upshift can be achieved, regardless of vehicle speed, if throttle opening is greater than 70% approximately.



ELEMENTS IN USE AT EACH POSITION OF THE SELECTOR LEVER