What is dual feed ing and how does it work

[headslide]

How do you do it what needs to be changed

 

[turbobitt]

Assuming you are referring to dual feeding the direct clutch pack, it involves connecting the two separate chambers within the direct clutch drum to increase the clamping force on the clutches. Typically only one chamber is used to engage direct and has a much less surface area for the hydraulic pressure to work against. Modifications to do this vary depending on the transmission.
AG


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[TexasT]

http://www.turbobuick.com/forums/th...ified-direct-drum-with-extra-clutches.237080/

You will need a billet shaft forward drum either before you dual feed or shortly there after to replace the one you twisted the splines off of. It really delivers a 2-3 shift.

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[gunzandgearz]

The direct c;utches are applied in reverse and and third, in other words they are used in reverse and third gear which is direct. When the piston gets fluid behind it to apply the clutches,it applies on only one half of the piston in rev. When it gets fluid behind it to go to third gear,direct, spinning same speed as engine, it pushes on the other half of the piston, because sealing rings keep the fluid separate from the two circuits. when you dual feed it youre putting fluid on both halves of the piston, on 2-3 shift, twice the pressure holding the cluthes.Most guys leave center sealing ring off the center support and plug the hole in bolt that holds center support for rev. circuit.As TexsaT said you better get billet shaft drum, because it will no doubt snap shaft. By the way this for 2004r trans.

 

[turbobitt]

The direct c;utches are applied in reverse and and third, in other words they are used in reverse and third gear which is direct. When the piston gets fluid behind it to apply the clutches,it applies on only one half of the piston in rev.

Not completely correct. The inner lip seal only seals in one direction and will allow oil to pass in both circuits in reverse. In direct the lip seal keeps oil in one chamber only. Reverse typically is feed to both circuits in the valve body for more clamping force in reverse.
AG.

 

[gunzandgearz]

not tryimg to give breakdown on complete circuit from pump to clutch drum apply just give the guy a little info on how it works.

 

[77 cruiser]

Gotta ask why do we need all the clamping force in R?
They should have been built the other way around from the factory.

 

[TexasT]

I think gm over engineered rev in the turbohydramatics. I think that is what fails first(rev) so they over did it. Just my opinion. Maybe someone has an actual reason.

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[gunzandgearz]

Its not just gm every manufacturer does it, its because the engine is turning in one direction and trans is turning in other direction fighting engine torque , and trying to move heavy vehicle. the clutches are just a brake and it takes a lot of clamping force to get this job done. Ever been into a stick shift, the rev gears are usually larger and have straighter cut gears.Hope this helps maybe someone else can chime in on this.

 

[turbobitt]

Gotta ask why do we need all the clamping force in R?
They should have been built the other way around from the factory.

There are reasons. Think about backing a heavy trailer full of stone up a driveway really slow with a load of dirt on the back of a truck. There is not much throttle angle to produce a lot of line pressure. So the factory designed the reverse circuit with extra line pressure and surface area on this clutch pack. The extra pressure comes from using an additional reverse boost pressure on the pressure regulator valve.
AG.

 

[gunzandgearz]

More good info, by the way , car looks good leaving line looks like it flies.

 

[gunzandgearz]

By the way, looked at oil flow schematic, and youre correct it feeds both sides of piston in rev.Just curious though, on the reverse question,whats the difference in going up the hill in rev. with heavy load if gravel, and going up hill in forward gear at same throttle pressure and no forward boost valve.

 

[turbobitt]

By the way, looked at oil flow schematic, and youre correct it feeds both sides of piston in rev.Just curious though, on the reverse question,whats the difference in going up the hill in rev. with heavy load if gravel, and going up hill in forward gear at same throttle pressure and no forward boost valve.

Almost always have higher throttle angle/TV pressure going forward since the operator has more control. The reverse band may also require this pressure for the extra holding power.
I'm sure there are more technical reasons.
AG.

 

[TexasT]

The rev boost valve also increases pressure in manual low and manual 2, as well as rev so you don't need throttle angle increase to get the pressure up. It is already there when you have the shifter in one of those positions.

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[gunzandgearz]

That is correct but that wasn't the question, the question was why do they build up the pressure in rev, automaticly, and if you put a pressure guage on both circuits at idle, first in rev. and then in manual low what happens. you have to have it in rev. no matter what, its built in and that's for a reason. nobody is going to be putting a heavy load on kia but check line pressure in reverse see what you get.

 

[TexasT]

Not sure on the KIA, but on my 2004r here are my results.



I feel that the larger reverse boost valve is cheap insurance on a performance 2004r though not all feel that way. If a driver shifts into low they are doing something out if the ordinary as pointed out by turbobitt. The engineers saw fit to increase the clamping force to help with deceleration, backing up an incline, or other tasks that might hurt clutches when pressure would not be raised by throttle application.

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[gunzandgearz]

All good information here,when we have discussions like this it helps the less informed on transmissions as well as sometimes even sheds the light on issues that even the pretty well informed guys can learn.By the way TexasT you don't know where I can get a good no rust not bent GS hood do you.

 

[TexasT]

I can keep an eye out. They pop up now and again. We are in dfw. The problem comes in shipping it.

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[chris718]

Gotta ask why do we need all the clamping force in R?
They should have been built the other way around from the factory.

Because the output shaft is turning opposite the input shaft , increased clamping force was found to be necessary to eliminate slippage when coupling components . Also if a loaded vehicle attempts to accelerate in reverse up an inclined angle plane the same increase in pressure was found to be necessary.

 

[gunzandgearz]

Im south and west of okc so right down the road basically. keep eyes peeled I would appreciate it.