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I am contemplating a swap of two transmissions, both of which use a PWM TCC and PC valve. The problem is that the valves operate on different frequencies between the two transmissions. This swap has been done before but I can't find anyone who is willing to tell me how they did it. I found this converter but it doesn't get me exactly where the frequencies need to be:

PWM Converter Board

How close do they NEED to be?

The original valves operate at -42hz and +614hz. The valves I'm wanting to go to are +32hz and +292.5hz respectively.

The frequency is determined by the TCM, I think the valves are just dumb valves for the most part. Does it even matter what valve I use? My understanding of the way that these things work is basically the valve can't open or close all the way as fast as the TCM applies voltage and therefore the amount that the valve opens is proportional to the overall duty cycle being put out by the TCM.
 

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Discussion Starter #2
Well shit ... I'm getting close to answering my own question. I'm finding that some sources list the valves as the same exact part whereas others do not. This is hinting that the valves don't in fact matter. I'm still wanting to hear from those more in the know though.
 

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I'd bet on them just being dumb solenoid valves that don't care about frequency, just on time.

One trans might use more on time to get the same result out of the other. That's what I'd be worried about. Get all kinds of slip codes (or just a burnt up trans if it doesn't have such diagnostic features)
 

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Boht transmissions have the line pressure PWM controlled and an input and output speed sensor. They both track how long the shift takes and vary pressure to make it right. Both have a table telling you how much they are having to compensate. I would think that it would be hard to burn one up if you were paying attention to it.

Plus, I think what you are referring to is reaction time. The frequencies are in hz, that's thousands of cycles per second. The valve isn't going to move that fast. Even a 1hz frequency is faster than that valve is capable of moving. I think the frequency has more to do with overcoming stiction, friction, etc within the actual valve so that it reacts smoothly and quickly without getting stuck. At least that's what I've read about pulse width modulation.
 

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Plus, I think what you are referring to is reaction time. The frequencies are in hz, that's thousands of cycles per second. The valve isn't going to move that fast. Even a 1hz frequency is faster than that valve is capable of moving. I think the frequency has more to do with overcoming stiction, friction, etc within the actual valve so that it reacts smoothly and quickly without getting stuck. At least that's what I've read about pulse width modulation.
I meant one computer having the line pressure duty cycle at say, 50% for a part throttle shift under such and such conditions. Then the other one calls for 30% for the same shift. Just 'dumb' fixed tables in the computer.

But with how advanced you say they are, I wouldn't worry about it one bit.
 

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I meant one computer having the line pressure duty cycle at say, 50% for a part throttle shift under such and such conditions. Then the other one calls for 30% for the same shift. Just 'dumb' fixed tables in the computer.

But with how advanced you say they are, I wouldn't worry about it one bit.
I can always copy from one table to the other if that's the case. And you're right, I'm sure that's probably different.
 

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A hertz is one cycle per second. A KHz is one thousand cycles per second.
Hertz - Wikipedia, the free encyclopedia
If you don't trust wikipedia then here is another source.hertz (unit of measurement) -- Encyclopedia Britannica
You're right, thank you for correcting me. But the general logic I think applies the same. Those valves aren't doing anything as fast as 42 times per second much less 614. They're averaging the duty cycle which is exactly what PWM is all about.
 

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Solenoids are just inductors on the inside (Coil). They are stupid & do not care at all about the frequency. Now, if there is a circut board to interpert between the signal & solenoid, you are SOL.

Ed
 
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