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Home >> Cadillac >> 2007 >> Escalade ESV >> Repair and Diagnosis >> External Pages >> Different car >> Section 1085 (Automatic Transmission - 4L60-E/4L65-E/4L70-E - Removal & Installation, Service, Overhaul, Troubleshooting & Diagnosis) >> Description & Operation >> Automatic Transmission Hydraulic Diagrams >> Overdrive Range, 4-3 Downshift >> Notes

Overdrive Range, 4-3 Downshift: Notes

WARNING: This page is about a different car, the 2008 GMC Sierra and 2008 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

When the transmission is operating in fourth gear, a forced 4-3 downshift occurs if there is a significant increase in throttle position. At minimum throttle, the vehicle speed decreases gradually (coastdown) and the PCM commands a 4-3 downshift. The PCM also initiates a forced 4-3 downshift when the throttle position remains constant but engine load is increased, such as driving up a steep incline. To achieve a 4-3 downshift, the PCM de-energizes the 1-2 shift solenoid valve and the following changes occur to the transmission's electrical and hydraulic systems: