Tech Tips (by ALLDATA): Chevy truck won’t shift

TECH TIPS (courtesy of ALLDATA)

Mileage: 136,445

Problem: The tech noticed that the fluid pressure switch “E” PID was reading “OFF” in all gear selections. It should read “ON” in Reverse, Neutral, 4th and 5th. It should read “OFF” in gears 1, 2, and 3. Shift solenoid “E” was being commanded “ON” and “OFF” properly at the ORN/WHT wire of the transmission connector (C175), which confirmed that either the pressure switch was bad or there was no pressure reaching the pressure switch through the valve body.

Details: The tech dropped the pan and removed the Pressure Switch Manifold, leaving the harness hooked up along with the scan tool. Using a pencil eraser to press on the diaphragm of pressure switch “E,” scan tool data confirmed that the switch could be activated from “ON” to “OFF” consistently. That confirmed that the switch, wiring and module were all functioning properly. The tech also checked the shift solenoid and it clicked every time with power and ground applied. The tech then removed the valve body and found shift valve “E” was sticking in its bore.

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Confirmed Repair: The valve body was sublet to a transmission shop to be rebuilt. The rebuilt valve body was installed and the transmission shifting problem was resolved.

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