The valve body is a part of an automatic transmission that aids in the gear shifting process. But, like any mechanical device, problems may affect the valve body.
The valve body controls the timing of the gears within an automatic transmission. It uses a combination of fluid pressure detection and hydraulic signalling to control the changing of gears and the activation of the clutch.
Though many parts can fail on an automatic transmission, symptoms of a damaged valve body include incorrectly timed gear levers, or no shifting at all. The valve body consists of multiple springs and valves; if the springs fail, the valves cannot open and close.
A repair technician may rely on diagnostics tools to detect damaged components in a vehicle. If the valve body fails, an error code is sent to the vehicle's on-board computer. The diagnostics tool will read the code and offer assistance with the best repair strategy.