Chart C-8B, 4T60 Transaxle Shift Solenoid Functional Check - 1992 3.8L PFI (VIN 1)
The 4T60E transmission uses two solenoids to control shifting. Shift solenoid "A" and shift solenoid "B". See SHIFT SOLENOID OPERATING SEQUENCE table for solenoid operating sequence.
PCM monitors TPS and vehicle speed versus engine speed to determine the correct shift points. If PRNDL position indicates manual low position, PCM will keep both solenoids energized until 54 RPM at which point PCM will force a shift by de-energized solenoid "A". Manual 2nd and manual 3rd are controlled hydraulically within transmission. See Figure.