1951 Pontiac Chieftain

[PhilA]

Is it me or is the transmission a bit sweeter now, too?

It's cold outside. It plays ball when it's cold.

[PhilA]

Found the final piece of the jigsaw. The trailing points had come undone slightly, enough to be loose but tight enough to not easily be visible.

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Timing stays where it's put now, which is good.

Phil

[PhilA]

Today a box arrived.

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Inside, an analog computer from a Cadillac.
It's filthy and jammed up with old type A fluid that's congealed.

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I don't think it's been apart before. I'll know better when I can get the pistons out and inspect. Bought a can of Chem-Dip to soak the parts down in, hopefully that'll free then up.

Phil

[PhilA]

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A not insignificant amount of scrubbing later and it's all clean and working again.

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Reassembled correctly; the gearbox wouldn't have worked at all the way it was put together, with one of the valves in backwards...

[PhilA]

Put the new valve block in this afternoon.
It's fixed two things, it doesn't engage the parking pawl going into reverse any more, and in top gear it doesn't shudder any more, I think it was engaging two gears at once.

It hasn't fixed the 1-2 shift issue when hot but now if I push hard on the throttle that increases the compensation pressure and boosts the line pressure, making it change gear properly occasionally.

Cold though it changes beautifully

[PhilA]

No, can't be the servo, not the way it's plumbed. Now I'm confused.

[PhilA]

Only thing I can think of at this point is the governor is getting hung up.

Cold, it shifts like honey

[SiC]

I know little about these things but I know on Aisin Warner boxed commonly used on Volvo/Saab/Renault/others, the bores wear enough that ATF leaks through only when hot. Thus giving very hard, car shaking shifts.

[DodgeRover]

Possibly stupid solution fit a transmission cooler?

[PhilA]

I know little about these things but I know on Aisin Warner boxed commonly used on Volvo/Saab/Renault/others, the bores wear enough that ATF leaks through only when hot. Thus giving very hard, car shaking shifts.

That is a problem with these too, but normally that's diagnosed by observing the oil pressure- when the shift happens there is a sudden demand for oil and if it leaks, the pressure drops significantly, screwing up the controller and making the jerky change.
This is within tolerance on oil pressure as per the manual, never drops below 60psi, doesn't lose pressure even on the 2-3 change where it's doing two things at once.

It's like it's just not being instructed to change gear until the road speed is high enough - making me suspect the governor might not be acting correctly.