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Discussion Starter #1
Hi,
Got a turbo 400, new build alto clutches, all new steels and seals. Fairbanks shift kit 20812. Car moves in 1st may shift to 2nd if you let off gas,second is mushy, could not get to shift to third. Did all the mods to the vb and replaced the pressure regulator spring as per instructions. no transbrake installed. checked line pressure, has 190 psi but when go to reverse, pegs gauge about 300psi. My friend call Fairbanks and they told him sounds like struck pressure regulator valve. This trans was built about a year ago and sat in the car until now, no fluid until now except what I used to assemble with. could the pressure regulator be stuck or any info on where to look would be appreciated. Have built many transmissions, first turbo 400 with an issue. Thanks, racer1979:)
 

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Discussion Starter #3
Hutch,
No, I haven't driven the vehicle. I built the trans for my friend and he just got around to getting the vehicle running. It is a 72 chevy truck with a turbo diesel in it. I know the support bolt is tight. You don't think over 300psi in reverse is a bit much? I could check the govenor. He is afarid to really drive the vehicle, doesn't want to burn it up. Other thoughts? What should I look for with the govenor? Thanks, racer1979
 

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It could be a modulator problem as well.being a diesel,is he using a vacuum motor to control vacuum to modulator.If there is little or no vacuum it could cause very late 1-2 shift and no third.190 psi should be fine at a stall in drive.get him to check pressure at idle as well,if it is still at 190 that could be part of the problem.
 

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300 at idle is high but not excessive if you have no vacuum at the mod valve (not sure how you performed the test). Look at the modulator controls as suggested and you will find your problem. Your dealing with a tricky deal there.


Hutch
 

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A thought just came to mind.I'm not sure what the kickdown solenoid controls.But if it's govenor pressure.Is it possible if the solenoid is exhausting govenor pressure (stuck open)that could cause late or no upshift as well.I've had a solenoid fail a while back but can't remember what it caused.If i'm way off base here please set me straight.
 

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Discussion Starter #9
Hi,
There is no modulator on the trans, only a plug that came with the kit. There is no kickdown hooked up, solenoid is there. The kit says it is full manual shift there is no automatic shifting. I won't be able to actually try and drive it with a gauge until early next week. The direct is dual fed. Thanks, Racer1955
 

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Discussion Starter #11
Sorry about the confusion, no the governor is not wired open. There was nothing in the instructions about doing that. The kit had 2 spacer plates and gaskets, a couple of springs for the shift valves in the valve body a plug for the modulator. and pressure regulator spring. a ball to plug the valve body to prevent the override in first. Thanks, Racer1979:)
 
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Sorry about the confusion, no the governor is not wired open. There was nothing in the instructions about doing that. The kit had 2 spacer plates and gaskets, a couple of springs for the shift valves in the valve body a plug for the modulator. and pressure regulator spring. a ball to plug the valve body to prevent the override in first. Thanks, Racer1979:)
Did one of the plates block the governor feeds?
 

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Discussion Starter #13
Hi,
To be honest with you, I am not sure. I can check when I look at it early next week. I don't have the instructions in front of me, my friend has them in another town. It may show on them. Sorry. Thank you, Racer1979
 

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Discussion Starter #14
Update: I am going over my friends house tonight to check this out. Now he tells me that it has 1st gear and reverse but, when he tries to shift to 2nd it kind of shifts but when he gives it more throttle it goes away. It has a Fairbanks 20812 shift kit in it, with this kit installed in the stock valve body it it now full manual standard pattern. There is no third gear. He also says that the pressures are about 190psi in all gears except reverse and that is about 350psi, it pegs his 300 psi gauge and goes past it.
I did upgrade the direct drum and it has the 34 element roller. If you held it with the roller up and the clutches down, it did turn freely clockwise and locked up counter-clockwise. Any thoughts before tonight. Thank you, Racer1979
 
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