4EAT Line Pressure control.

[Trevor]

Originally Posted by elninoalex

OK mate. What makes you believe it is closed? Is it because the check ball is held on the seat by the return spring?

This is the C solenoid opened up:

When it is not electrically on, the valve is hydraulically open. When the valve has the pilot pressure applied to it, it pushes the check ball back against the armature, and the pilot pressure flows through the valve.

When the Duty cycle Pulse is increased, the magnetic push on the armature, applies pressure to the ball to push it into the seat area to restrict the oil flow. These hydraulic solenoids use the check valve to close the valve when the engine is stopped to prevent the valve body from draining the oil out of the passages, but when the box is running the check ball is pushed open by the pilot flow.

Is that what you mean?

Harvey.

Thanks Harvey, it's much easier to visualize by seeing the internals. So what's considered 'normal' position would be when it has pilot pressure but is not electronically energized?[/QUOTE]

elminoalex,

Do not be fooled, your logic is exactly correct. BEWARE !

The valve illustrated by Harvey and that which he instructs you to visualize, is NOT in fact an "A'' or "C" type valve. It is a free floating control valve as used "!,2 & 3". Sly tactic to, be sure. You will note that a spring is not included as part of the valve illustrated.

It is pointless for me to illustrate the proper valve, as I can not do so while it is in place, but I trust that another will confirm what is correct. It should be appreciated that differences between the free floating and normally closed pattern, can not be established from the exterior, without electrical activation and the application off pressure. All is described in an honest description, included in one of my earlier posts.
Harvey is a master of sly deception deigned to draw the gullible about him.