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700R4 mod that I saw in a mag...

jonrpick

jonrpick

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Anybody seen or using this?

It's the "Constant Pressure 700R4 Valve Body" from TCI.

http://www.compperformancegroupstor...Screen=PROD&Store_Code=TC&Product_Code=376020

The idea is that the pressure isn't controlled by the TV cable, so you don't have to worry about having it adjusted properly and burning up your tranny. The TV cable is still used, but just to set the shift points...

Seems like a cool idea. Thoughts?
 
kgblazerfive said:
Does seem like its a cool idea but is the TV cable that hard to adjust, well 287.00 dollars hard. :confused:
Click to expand...

Agreed, but I like the idea of being able to set the shift points with the cable and the whole "not having to worry" idea...
 
push the button in on the side without touching the throttle, then kicking the throttle linkage open to WOT is all that hard? i think not.
 
Yipes, you can dig up a "new" 700R4 for $300.

In related news, does anybody have a link to info on setting up the TV cable? I'm gonna have to do it soon.
 
54inches said:
The TV cable can be a bitch if you do not know what you are doing. Not quite like a 400.
Click to expand...

redneckdude said:
push the button in on the side without touching the throttle, then kicking the throttle linkage open to WOT is all that hard? i think not.
Click to expand...

Honestly, for me, I'm so obsessive about stuff like that, I wouldn't feel good about it unless I had a pressure gauge for the tranny on the dash. I'd always wonder if It was right. I like the idea of the constant pressure mod, just for removing doubt. As 54inches said, it's not the same deal as with a 350 or 400. If you don't get it right, you could fry the tranny.

I'm buying a transfer case tomorrow from a dude who fried his freshly rebuilt 700 after an improper TV cable adjustment...
 
When the guy who built mine did it I got to watch, it was in my Astro with no engine cover on. It was was basically wide open throttle engine off and he made sure the cable was tight the metal on inside of the the sleeve.
I think that you have to drive pretty far with a poorly adjusted one to ruin a trans. I did it by the book and got really close took it to him cuz I wanted it to lay rubber when it shifted.
 
I have seen those. never understood them... I just wonder. Why? Adjusting the TV cable is not rocket science. Pretty basic easy stuff, it stays adjusted once you do it. I haven't touched mine in years. Don't see a reason for a 250+ dollar trans kit that does nothing more than a properly adjusted TV valve does for free:what:
 
yeah... uhh adjusting the TV cable aint hard at all.. u press a button near the carb/tbi.. and have someone else slam the gas pedal.. let it ratchet to where it goes.. and ur set.. did this and mine works perfect.
 
kgblazerfive said:
When the guy who built mine did it I got to watch, it was in my Astro with no engine cover on. It was was basically wide open throttle engine off and he made sure the cable was tight the metal on inside of the the sleeve.
I think that you have to drive pretty far with a poorly adjusted one to ruin a trans. I did it by the book and got really close took it to him cuz I wanted it to lay rubber when it shifted.
Click to expand...

Thunder said:
I have seen those. never understood them... I just wonder. Why? Adjusting the TV cable is not rocket science. Pretty basic easy stuff, it stays adjusted once you do it. I haven't touched mine in years. Don't see a reason for a 250+ dollar trans kit that does nothing more than a properly adjusted TV valve does for free:what:
Click to expand...

Can a pressure gauge be easily added to the 700R4 to monitor it and make sure it stays out of the danger zone?

I don't know a whole lot about the way the guts of the 700 work. I'd like to know more.

Does pressure rise as throttle is increased? What's the safe minimum pressure limit before damage starts to occur? Does RPM affect pressure, or does pressure need to increase with RPM in order to keep everything in check?
 
Well the constant pressure valve body does more than eliminate the TV cable. If that was all it did it wouldnt be worth it. Its right there in the name "constant pressure" Thats ALMOST a manual valve body effectively, meaning whatever gear you put it in its going in that gear and staying there. Basicaly it would make it shift the same as a th350 or th400

Ever drive a stock 700r4 and drop it down into first and floor it? It WILL NOT stay in first until the trans blows up. It will shift itself into second when the pressure peaks. Its a function from the factory, that was supposed to aid in towing.

This would come in handy in any situation you need the trans to stay in the gear you put it in. OR downshifting. Likewize going 70mph and you drop the shifter down to second gear, nothing will happen in a stock 700r4 until the pressure drops down.

Technicaly GM claimed a 700r4 was designed to down shift while towing. You are supposed to be able to drop the shifter down to 1st gear at any speed and as you apply the brakes and slow down enough to be safe the trans is supposed to downshift at the correct time.

Wouldnt it be great if they actualy worked the way they was designed to?

WARNING! I do not sugest anyone runs out and tries this. I honestly belive that their plans for the 700r4 failed. This was explained to me by a GM factory trained transmission man and he also said it does not work like they intended.

I have herd of some of them working this way but it seams a hit and moss situation, Some do and some dont.

Before anyone asks me to get more techinical this was the way it was explained to me. I AM NOT a transmission expert.

I looked into this valve body about a year ago, but I desided to have it built beefy and leave the original shift functions.
 
original balzer said:
Well the constant pressure valve body does more than eliminate the TV cable. If that was all it did it wouldnt be worth it. Its right there in the name "constant pressure" Thats ALMOST a manual valve body effectively, meaning whatever gear you put it in its going in that gear and staying there. Basicaly it would make it shift the same as a th350 or th400

Ever drive a stock 700r4 and drop it down into first and floor it? It WILL NOT stay in first until the trans blows up. It will shift itself into second when the pressure peaks. Its a function from the factory, that was supposed to aid in

This would come in handy in any situation you need the trans to stay in the gear you put it in. OR downshifting. Likewize going 70mph and you drop the shifter down to second gear, nothing will happen in a stock 700r4 until the pressure drops down.

Technicaly GM claimed a 700r4 was designed to down shift while towing. You are supposed to be able to drop the shifter down to 1st gear at any speed and as you apply the brakes and slow down enough to be safe the trans is supposed to downshift at the correct time.

Wouldnt it be great if they actualy worked the way they was designed to?

WARNING! I do not sugest anyone runs out and tries this. I honestly belive that their plans for the 700r4 failed. This was explained to me by a GM factory trained transmission man and he also said it does not work like they intended.

I have herd of some of them working this way but it seams a hit and moss situation, Some do and some dont.

Before anyone asks me to get more techinical this was the way it was explained to me. I AM NOT a transmission expert.

I looked into this valve body about a year ago, but I desided to have it built beefy and leave the original shift functions.
Click to expand...

Interesting that you bring that up. I'd forgotten about the fact that I've never been able to hold my 700 in one gear without it shifting (against my control).
 
Yea its supposed to know when to shift all by its self. In order to be constant pressure it would have to eliminate thiose self shifting crap.

Personaly I remember a friends truck with a 700r4 and a worn out 305. We was trying to get up a steep hill and he would pull it into first and start up the hill. Then it would shift by its self and he would power out (cuz the engine was weak) I would bet he could have climbed it if it wasnt for the automatic-no-matter-what stupidness.

I have only owned 3 700r4's the first 2 burnt up and got replaced by sm465 manuals. The third one is in my (now my bros) 1990 gmc suburban. I had it rebuilt and beefed up with every trick.

I cant remember all the mods but there was somthing about a th400 part?? corvette servo a mild shift kit and a few other things.

I do know it will snap your neck when it shifts (or blow out the stupid 10 bolt.....twice, spider gears 1 time and ring/pinion the second)

Now the bad news it was a little over $3k with them pulling rebuilding and replacing, the trans. I guess thats what happens when you say I want EVERY beef up mod you can do but still want daily driver ability.
 
I just bought an '84 3/4 ton 4x4. It has a nice shifting 700R4. I'm gonna' put a guage on it. I WANT TO KNOW! I'm not convinced the factory "floor it" setting is perfect, just somewhat close. I've played with a few 200's and 700's. The guage is da KEY! Ug PS, That 'Burb is pictured at your left in Yosemite. It's 3000 miles away now, in my yard. Got another almost identical from Texas w/BANKS. Mushy 700...

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uglytruk said:
I just bought an '84 3/4 ton 4x4. It has a nice shifting 700R4. I'm gonna' put a guage on it. I WANT TO KNOW! I'm not convinced the factory "floor it" setting is perfect, just somewhat close. I've played with a few 200's and 700's. The guage is da KEY! Ug PS, That 'Burb is pictured at your left in Yosemite. It's 3000 miles away now, in my yard. Got another almost identical from Texas w/BANKS. Mushy 700...
Click to expand...

If you do this, let us know how you did it (where you tapped in for the pressure sensor / sending unit). I'm very curious.
 
The pressure port is above the shift lever on the driverside...1/4" NPT

As I mentioned in another thread, when I finish building my 700, I'll be running a 300lb pressure gauge permenantly out on the hood, next to fuel psi and vacuum....

here's some basic line pressures your looking for...

Range Minimum Maximum
Park 90-110 190-230
Reverse 95-120 200-300
Neutral 90-110 190-230
Overdrive 90-110 190-230
Drive 90-110 190-230
Second 185-230 185-230
Low 185-230 185-230

BTO requires you to go thru this test for warranty http://www.tvmadeez.com/pressure_test/index.php

I have heard of the "constant pressure" piece but haven't heard from any tranny experts on if it's good or bad... Certainly seems like it could save your tranny at some point... I'll have to ask my tranny mentor about it before we build my 700... I'm already going nuts with EVERY available upgrade you can run, might as well consider this...
 
Just wanna subscribe to this one...

Putting a 700r in my 1st gen this coming summer.
 
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