Is it normal for a freshly rebuilt 904 to downshift all the way from 3rd to 1st (~5000 RPM) if the kickdown is adjusted too far out?

I figure I just need to make some finer adjustments to my kickdown mechanism, but this is so far off the previous behavior of the transmission before the rebuild that I figured I'd ask before I damage anything. I didn't even know the 904 could downshift all the way from third to first. It also upshifts higher than it did before, even though we didn't adjust the governor weights or valve springs. All we did was a soft rebuild. Prior to the rebuild, the thing would not downshift nearly as hard OR stay in low gear under acceleration nearly as long as it does now, even with the kickdown linkage adjusted to maximum actuation.

Maybe this transmission has just been worn out as long as I've owned it, so I'm not used to this behavior. As long as I can get the shift points dialed in to be a little less aggressive, I'll be happy. I'll just need to do some more test drives. I'm just worried we broke something, and I really don't want to over-rev my freshly rebuilt engine.

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Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing

Sounds like it is working better than before, to me. You should be using the shifter on the track to control what gear anyway. If you have the kickdown lever adjusted so it goes all the way back when you are at WOT, then it can shift down from 3rd to 1st directly. Sounds like maybe you increased the line pressure during the rebuild and/or freed up the kickdown lever/valve??

In short, the kickdown lever adjustment has a huge impact on the shift points and firmness.

Best,

Lou

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Home of Slant6-powered fun machines since 1988

That makes me feel a lot better. I don't want it downshifting quite so aggressively during an endurance race, so I'll make some further adjustments to the kickdown mechanism.

_________________
Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing