What is line pressure in automatic transmission?

What does line pressure do in a transmission?

The pressure generated by the oil pump is channeled to mainline, governor, and throttle pressure valves to control and lubricate the transmission.

What is normal transmission pressure?

Place the transmission in forward position and operate the transmission to 600 RPM. The pressure should read 40 to 70 psi.

What means line pressure?

Definition of line of pressure

: a broken line joining the points of resultant pressure between the voussoirs of an arch or buttress.

What causes high line pressure in a transmission?

Pressure that are lower than specifications are usually caused by leaking seals or a worn oil pump. Higher than normal pressures are usually caused by a faulty pressure regulator. These specifications for an electronic transmission require that the current to the Pressure Control Solenoid be measured.

Is higher line pressure good in transmission?

Line pressure is just one of the components that contribute to the torque capacity of the transmission. First, it’s not the speed of the application of a clutch but the holding strength once the clutch is applied that contributes to strength. In this respect higher line pressure will give higher torque capacity.

How do you control line pressure?

The fluid is typically pressurised by a pump which is turned by the engine, with a mechanism to control the pressure to the optimal pressure for the current conditions. Some transmissions accomplish this with a pressure relief valve, and some transmissions use a variable geometry pump.

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What causes low transmission line pressure?

Line pressure is normally effected by throttle position and the gear range. Pressure that are lower than specifications are usually caused by leaking seals or a worn oil pump. Higher than normal pressures are usually caused by a faulty pressure regulator.

Which of the following can cause low line pressure in an automatic transmission?

A line pressure test shows low pressure at idle in all ranges on an electronically controlled automatic transmission. Which of the following can be the cause? A problem in the oil pump or oil pump pressure regulator will cause low pressure at idle in all gear ranges.