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Discussion Starter #1
Ok, I'm almost done with my project and now I've run into a trans problems. TH400 with a CK performance tb. Solenoid works with engine off. However, once I crank the car. The solenoid will not engage. I have 12.70 volts to the noid (running or not) 150psi trans pressure in any gear or park. I can push the noid in mannually and everything works fine. I have tried two noids. Any advice would be appreciated.
 

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i would say that there a cross leak in vb/ plate to case area... it pressuring the bottom side
of the TB valve were the sol cant push the valve.





Roger
 

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Discussion Starter #3
You may be on to something. There is no gasket between the two. Instructions said one wasn't needed.
 

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use a big sanding bloke to true / flatin the case. dose the TB valve have a feed hole down the center of it?to help push the valve off?
 

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Discussion Starter #5
Not sure about the hole. Would a gasket work?
 

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Are you sure you are in low gear when testing? What happens when you engage the solenoid in neutral? Does it engage? Is it much harder to push in the solenoid plunger when the car is running then it is when its not running?


Hutch
 

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Discussion Starter #9
Yes I have tried 1&2 gear it is supposed to work in either gear. Have not tried neural. I do know that there is not a gasket between the vb and plate. Not sure if my trans Guy put one between the plate and the case. Would this cause this type of problem? Yes, easy to push noid while engine off hard while on.
 

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If its hard to push when its running then it may be a problem with the fluid release portion of the circuit. Just wait until you get a hold of Chris and see what he says first before you make changes.


Hutch
 

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Are you sure you are in low gear when testing? What happens when you engage the solenoid in neutral? Does it engage? Is it much harder to push in the solenoid plunger when the car is running then it is when its not running?


Hutch
That's what I'm thinking. I know on some brakes if a relief hole is not drilled you have to cycle the solenoid in neutral a few times to push the fluid out. Then put it in gear and see if it holds
 

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Discussion Starter #12
Thanks for all the input. Chris has been very helpful but just trying to get some help over the weekend.
 

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If it apply's in neutral and the wheels go backwards (reverse) then hold the brake on and pull it into 1st , then the brake should be on which will verify the circuits are ok. Then the problem is the valve feed. This may help with the diagnosis.


Hutch
 

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Discussion Starter #14
You nailed it. Can you help explain the valve feed? Do I need to modify the plate, get another vb or something else?
 

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Can't tell you how to fix it as I would have to study the hydraulics for a few moments to come up wit a solution. Somehow line oil got directed to the brake valve by mistake. I would wait until Chris gets in the shop monday and see what he says. Its his creation and im sure it will be a fairly simple fix.

Hutch
 

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The valve body does not use any gaskets on either side of the plate.Line pressure is present at the big land of the brake valve whenever the engine is running.Try pushing the button in park.Does the car jerk?It should.Try pushing it in neutral.Does the car jerk?It should.Note the pressure gage in these 2 ranges while testing.Should drop 20 to 30 psi down from the 155 and return back to 150.150 because the bleed hole in the drum usually results in a 5 psi drop when direct clutch is on.Same results should occur on the pressure gage with brake applied in 1st gear range.Try pushing the solenoid in by hand with the engine off.Now try it with the engine running and the selector in 1st gear range.Does it feel harder?Much harder to push?If so I suggest you have drive oil crossleaking into the passage that feeds the end of the brake valve .Because the solenoid is not as strong as the hand it cant force the oil out of the cavity or compress it (liquid is not compressible),the valve wont upshift.Check the case for flaness.Whetstone the case,plate and valvebody and this should be where your problem is.I do run all of the valve bodies on a trans on the dyno before I package them to make certain to the best of my ability they will function when installed.Good luck and let me know what happens or if you need additional help.
 

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Discussion Starter #17
Thanks Chris, I'll get the pressure readings before I call you. Can I flaten the case in the car?
 
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