4 передача на АКПП

[ilya_ka]

CONVERTER CLUTCH ENGAGEMENT
The torque converter clutch is engaged by the clutch solenoid on the valve body. The clutch can be engaged in third and fourth gear ranges depending on overdrive control switch position.
If the overdrive control switch is in the normal ON position, the clutch will engage after the shift to fourth gear, and above approximately 72 km/h (45 mph).
If the control switch is in the OFF position, the clutch will engage after the shift to third gear, at approximately 56 km/h (35 mph) at light throttle.

А вот выдержка из официального мануала по АКПП 42RE.


Но это всё не важно и не объясняет почему не включается 4я.