Adding part throttle kickdown 904

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mbaird

mbaird

mbaird
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What do I need to convert my 904 to a PTK ?
How can I tell which throttle body I have now ? The trany is from a 68 318 but has been modified over the years .

Is there a different servo or is it just a check ball modification.
I googled the subject but every thread stops short of details or gets derailed onto another subject.

Thanks
 
mbaird said:
What do I need to convert my 904 to a PTK ?
How can I tell which throttle body I have now ? The trany is from a 68 318 but has been modified over the years .

Is there a different servo or is it just a check ball modification.
I googled the subject but every thread stops short of details or gets derailed onto another subject.

Thanks
Click to expand...

After around 65-66 they are all pretty much the same VB, but some got the PTK and some didn't.
The entire PTK kit is an add on valve assy, so when you pull the VB down it's pretty obvious if it has it or not.
Nothing about the PTK kit involves splitting the valve body or messing with check balls.

Is this what you wanted to know?

In the pic below the PTK valve section goes where those springs and valve are sticking out and it is laying on top of the VB in the upper left of the pic.
VB's without it have a flat plate there over those springs and valve.

ptk.jpg
 
Last edited:
Yes.. that is what I needed.

Can I buy the needed components new or do I have to find a used one ?
 
Torque Flight Patty on ebay sells the PTK kits, or the parts can be pulled from a newer VB from a 727 or 903 either one.
When you find one make sure you get the 3 longer screws with it, as the plates use shorter screws.
The entire assy comes off as one section in one piece with the valves in it, so no worries about needing any other parts of the VB.

Oh, and you are welcome. :D
 
Patty's Ebay store is closed till June 8th for inventory ? Hmmm...
I will check my valvebody 1st to make sure it is not there before ordering. It might be there but malfunctioning. I just ordered a 5000 rpm governor assembly from A&A that I will need to install as well
 
You would know if it was there. I can't see how one would malfunction. Most problems with shifting is caused by missing or incorrectly adjusted throttle pressure linkages. TrailBeast is spot on with what he said. Also any 1971 and later 727 or 904 valve body has it. Well worth the add on to any transmission in my opinion. Makes the car so much more streetable.
 
I set my throttle pressure as per factory manual . I am not getting any kickdown unless I manually downshift. 1-2 and 2-3 upshifts seem to be correct.

I have the trany out while switching engines and got to thinking about the intro of PTK in 71 so I thought I would research it.
I will pull the pan and valve body to check tonight.
 
TrailBeast said:
After around 65-66 they are all pretty much the same VB, but some got the PTK and some didn't.
The entire PTK kit is an add on valve assy, so when you pull the VB down it's pretty obvious if it has it or not.
Nothing about the PTK kit involves splitting the valve body or messing with check balls.

Is this what you wanted to know?

In the pic below the PTK valve section goes where those springs and valve are sticking out and it is laying on top of the VB in the upper left of the pic.
VB's without it have a flat plate there over those springs and valve.

View attachment 1715189416

Like this ?
20180619_201151.jpg
20180619_201201.jpg
Click to expand...
 

The PTK section is on the top of the valve body (unfortunately):D but the plate looks kind of like the left pic but has 3 screws instead of 5.
 
Ok I think I understand now..
I will pull the valvebody sometime this week .

I have Tom Hands book on Torqueflites but he is somewhat vague on this subject.
 
mbaird said:
Ok I think I understand now..
I will pull the valvebody sometime this week .

I have Tom Hands book on Torqueflites but he is somewhat vague on this subject.
Click to expand...

Once you see it and do it you will be surprised how easy it is.
BTW, if you don't quote someone they don't know you replied.
I just happened to see it.
 
TrailBeast said:
Once you see it and do it you will be surprised how easy it is.
BTW, if you don't quote someone they don't know you replied.
I just happened to see it.
Click to expand...

TrailBeast, you seem to know this subject pretty well, so I have a related question.
The 904 in my Dart is from a 74, and it has the part throttle kickdown feature. Works great when cruising around town at light throttle. So at 25-35 mph if its already in 3rd, I can give it a little gas and it will shiftdown from 3rd to 2nd. If I'm above about 35mph it doesn't kick down unless I floor it. Is this an adjustment issue, or is this how they were designed to work?
 
MileHighDart said:
TrailBeast, you seem to know this subject pretty well, so I have a related question.
The 904 in my Dart is from a 74, and it has the part throttle kickdown feature. Works great when cruising around town at light throttle. So at 25-35 mph if its already in 3rd, I can give it a little gas and it will shiftdown from 3rd to 2nd. If I'm above about 35mph it doesn't kick down unless I floor it. Is this an adjustment issue, or is this how they were designed to work?
Click to expand...

That is by design, but a governor mod or change can fix that.
 
So when I install the 5000 rpm governor I ordered from A&A how will that effect the PTK ?
What is the relationship ?
 
mbaird said:
So when I install the 5000 rpm governor I ordered from A&A how will that effect the PTK ?
What is the relationship ?
Click to expand...

That's a good question and I was thinking about that the other day.
On one hand the new governor is going to delay the shift a LOT, and the part throttle kickdown would try to make it kick down with less throttle opening.

Now one thing a lot of people don't know is that to make a trans shift later it needs less fluid pressure to the valve body, and not more like it seems it would need.
More pressure moves the shift valve sooner, causing the shift to be earlier.
The governor will fight that due to the higher spring pressure or lighter valve that will move later as the centrifugal forces of the driveline spinning try to make the new valve move at higher spinning speeds.

Short answer is I don't know.:D
I would venture a guess that the PTK may not have any affect at all, because the new governor will override it.
Really, I don't know.
 
Hmmm... interesting.
I dont know autos well enough to visualize the whole process.
 
mbaird said:
Hmmm... interesting.
I dont know autos well enough to visualize the whole process.
Click to expand...

All you really need to know for sure is to do one at a time.:D
I would do the governor first, because you know you want it and know what it is supposed to do.
Then later you could add the PTK and see what it does if you want.
It's very possible you could end up not doing the PTK at all after the governor change.
 
TrailBeast said:
All you really need to know for sure is to do one at a time.:D
I would do the governor first, because you know you want it and know what it is supposed to do.
Then later you could add the PTK and see what it does if you want.
It's very possible you could end up not doing the PTK at all after the governor change.
Click to expand...

Hard to tell from your pic but I would say there is no PTK provision in this one.
 
I guess it does....
I have no idea as to what to look for. Notice any glaring issues or modifications ?
This trany was in a AHRA B-body Stock class car with a 318 and W2 heads. Ran 11.3s in the 70s/80s and was a class champion for a time.
 
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