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Th350 wave plate?

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Old Oct 20, 2024 | 03:49 PM
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Default Th350 wave plate?

Hi everyone

I wanted to instal my fully assembled pump with new gasket, lip seals and O-rings, but then I noticed this...
Is this normal?
It doesn't seem right to me... (Broken?)

I looked up the part buit I'm not sure of the name. Is it the 'intermadiate wave plate'?

Can I just assemble it and leave it like it is or should it be replaced anyway to avoid future damage?







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Old Oct 23, 2024 | 03:14 PM
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From: At my Bar drinking and wrenching in Lafayette Colorado
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The intermediate wave plate should be a solid, continuous piece without a slit or break in it. It is supposed to be "wavy." This cushions the impact when the intermediate clutches kick in, and produces a smooth shift.

Are you concerned about the wavy, non-flat appearance, or about the slit..? I can't see the slit having any impact on the wave plate's operation. It could produce a slightly softer and smoother shift. I stopped working on TH350 trannys in the mid '70s, and have not seen a "split" wave plate during my time building TH350s in the early to mid '70s.. It could be possible that Hydramatic introduced a split/slit plate in the later '70s that I am not aware of in order to smooth out the shift, so I would not discount the split plate from being legitimate. The waviness, however, is correct and legitimate.

Last edited by lars; Oct 24, 2024 at 12:49 AM.
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Old Oct 24, 2024 | 12:47 AM
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I always replaced them with another steel to firm up the shifts....

JIM
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Old Oct 24, 2024 | 12:52 AM
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From: At my Bar drinking and wrenching in Lafayette Colorado
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We did the same thing on our racing transmissions. Most people with brand new Chevy Caprices and secretaries with a new late-'70s Vette did not appreciate that "performance" upgrade...
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Old Oct 24, 2024 | 02:55 PM
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Yep. When I did the T-400 for my old 427 Camaro...I literally sat down with the GM manual and traced all the circuits through the trans. I discovered that just about everything in there was to "calm down" the shifts. So of course I defeated most of them.

That sucker produced high gear chirps at barely off idle throttle that jarred your teeth. Full throttle rattled the whole car.

I then went back home and reimplemented a few things to make it street drivable! LOL

Killer trans though!

JIM
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Old Oct 24, 2024 | 05:31 PM
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Thank you all guys for the replies!
I bought a new one online.

I didn't any picture on the internet of a wave plate that had that 'broken' split-washer look.
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Old Oct 24, 2024 | 11:48 PM
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From: At my Bar drinking and wrenching in Lafayette Colorado
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As noted, I've never seen one with a slit in it, either, but I don't see how a slit would alter it's intended function other than perhaps making the shift a little softer by making the wave a little easier to compress.
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Old Oct 28, 2024 | 03:51 PM
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My book for the T350C shows it as the intermediate clutch cushion spring and it has the slit shown in it
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Old Oct 28, 2024 | 04:44 PM
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From: At my Bar drinking and wrenching in Lafayette Colorado
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That doesn't surprise me. Cutting the slit would be a good, cheap way to soften that shift so it won't feel like a "performance" shift.
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