What affects shift valves to cause a downshift?
As vehicle speed increases, the governor pressure (affected by vehicle speed) increases until it overcomes throttle pressure and causes an upshift. A downshift occurs when throttle pressure overcomes governor pressure. This is because of the increased engine load. These two pressures control shift valve movement.
What would be noticed when a good shift solenoid is activated?
Those engine sensors determine when it’s time to shift gears based on speed. When the shift solenoid is activated, the plunger will open certain valves in the valve body to allow transmission fluid to enter. That puts pressure on the clutches and bands that cause the transmission to actually shift gears.
Why is my transmission downshifting hard?
Transmission Fluid Low or Poor Condition – Vehicles low on transmission fluid or that are operating with worn out or contaminated fluid are likely to experience hard shift conditions. Lack of adequate lubrication within the transmission can cause several problems, including hard shifting.
What causes an automatic transmission not to downshift?
One main reason why the automatic transmission in your car may not be shifting smoothly is the ECM is going bad. It is best to get this checked out by an experienced auto mechanic technician who understands the electrical system. Other indicators include bad connections within, or worn out sensors and faulty solenoids.
Where is the downshift solenoid located?
Transmission Shift Solenoid Location The Transmission shift solenoids are located inside the valve body of your automatic transmission. They are integrated into the valve body, and on some car models, you can see them without removing the valve body, while on others, you have to remove the valve body to reach them.
Can throttle position sensor affect transmission shifting?
The Throttle Position sensor measures the throttle position, which is controlled by the gas pedal. It is used to determine engine load and if it fails it can cause automatic transmission shifting problems.