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Topic Review (Newest First)
09-07-2011 08:38 PM
cadmanof50s Firstly the manual switch will activate the 4th lock up. (You don't need the ground lead at the manual switch ..it will do nothing.

The LED will light when the manual switch is active ( i.e. allows the TCC to lock) AND the transmission is in 4th gear.

If any part of that LED circuit shorts out to ground (accidentally) ..you're back to square one. It would create the same condition that we started with...the fuse will start blowing again.

Who built this circuit? That LED will receive full +12 volts. Many common LEDs will fry up unless there is some kind of current limiting device such as a resistor.

At this point I must ask, wouldn't you rather have TCC kick in automatically? Or is there a reason you want it to be engaged manually?


Vic
09-07-2011 07:11 PM
63ChevyII.com What would this do?



I'm thinking that the lockup wouldn't engage unless the trans was in 4th AND the switch was tured on. When the lockup is engaged, the LED would come on.
09-06-2011 09:35 PM
cadmanof50s Sure..

The manual switch basically bypasses the 4th gear pressure switch. Unlike your set up, this manual switch takes +12 volts which is present when the BRAKE is NOT ON and feeds it to directly to the TCC solenoid. Notice that the blue wire ends on the same 4th gear pressure switch terminal as the TCC solenoid is connected to. This effectively bypass the 4th gear switch. When turned on, the manual switch will therefore force the TCC to lock even when the transmission is NOT in 4th gear.

This is yet another wiring method for towing..because you can force the TCC to lock when you want it to regardless of the 4th gear.

To answer your question, no this would not create teh same short. As it is feeding +12 volts to a device that is expecting it. Secondly even if the 4th gear pressure switch is closed, it is conducting the +12v that has the same voltage source as the manual switch. Therefore regardless of any of these switch conditions, a short to ground cannot occur.

Vic
09-06-2011 08:51 PM
63ChevyII.com
Quote:
Originally Posted by cadmanof50s
"One thing I read somewhere is that if your pressure switch has two connections, it needs to be grounded externally. Is this not always true?"


Yes and no.

With the wiring you have it will work just fine the way it is (so long as teh switch is still good and you have cut the wire at pin D).

The way the pressure switch works is that when it senses enough fluid pressure, it merely closes the contact between the two terminals. There are some pressure switches with only one wire. In these cases it means that when the switch closes they create a direct short to ground..that is NOT your case).

Your TCC is a one wire. That means that the one wire must be activated by +12 BUT internal there is another wire that you can't see..that goes to ground. Remember that there are many ways to wire this system. What one person says out of context may not apply to all situations.

Hope this helps!!

Vic

Thanks for the explanation, that helps.

If you have a chance, could you try to explain this diagram to me, in particular the part that has the manual switch.



Does the manual switch bypass the the pressure switch? If the manual switch was on, and then the pressure switch kicked in, would this create the same sort of shorting situation that I have with my wiring?
09-06-2011 08:46 PM
63ChevyII.com
Quote:
Originally Posted by Crosley
63ChevyII ... welcome to Hotrodders.com

I moved your posts to a new thread here so as to provide a location for your problem
Thanks Crosley!
09-06-2011 07:50 PM
cadmanof50s "One thing I read somewhere is that if your pressure switch has two connections, it needs to be grounded externally. Is this not always true?"


Yes and no.

With the wiring you have it will work just fine the way it is (so long as teh switch is still good and you have cut the wire at pin D).

The way the pressure switch works is that when it senses enough fluid pressure, it merely closes the contact between the two terminals. There are some pressure switches with only one wire. In these cases it means that when the switch closes they create a direct short to ground..that is NOT your case).

Your TCC is a one wire. That means that the one wire must be activated by +12 BUT internal there is another wire that you can't see..that goes to ground. Remember that there are many ways to wire this system. What one person says out of context may not apply to all situations.

Hope this helps!!

Vic
09-06-2011 07:39 PM
63ChevyII.com
Quote:
Originally Posted by cadmanof50s
Correct you DO NOT need anything at pin D if you are not towing.

(sorry it appears as pink on my computer). Keep in mind that the abuse of fuse blowing may now have damaged the 4th gear pressure switch. Yes teh fuse is supposed to protect it..but current must be high enough to blow the fuse...unfortunately that current may also be high enough to damage the switch.
Thanks, I'll let you know how it works out. I dropped the car off today to get the exhaust done, but I should have it back this weekend or beginning of next week.

I really hope this works, I don't want to pull the pan off again.

One thing I read somewhere is that if your pressure switch has two connections, it needs to be grounded externally. Is this not always true?

Here are some pics of the car:
63ChevyII.com
09-06-2011 07:38 PM
Crosley 63ChevyII ... welcome to Hotrodders.com

I moved your posts to a new thread here so as to provide a location for your problem
09-06-2011 07:34 PM
cadmanof50s Correct you DO NOT need anything at pin D if you are not towing.

(sorry it appears as pink on my computer). Keep in mind that the abuse of fuse blowing may now have damaged the 4th gear pressure switch. Yes teh fuse is supposed to protect it..but current must be high enough to blow the fuse...unfortunately that current may also be high enough to damage the switch.

You can just cut the wire comming from pin D. When the internals are working correctly, +12 volts at pin A will cause the TCC to lock. This can be done from your manual switch at teh dash or as many people do, via the brake switch and a vacuum switch.

Vic
09-06-2011 07:29 PM
63ChevyII.com
Quote:
Originally Posted by cadmanof50s
then things should work just fine with the pink wire cut off.

Just so we're clear (wires show up as orange and purple on my computer), PIN A wire or PIN D wire? If I understand correctly, you're saying to get rid of the PIN D (purple & chassis ground) wire.
09-06-2011 07:26 PM
cadmanof50s OK I see the problem.

Obviously you are not towing. That being the case remove the wire at the dash switch which is pink. In fact, cut it and tape it off a couple of inches from the transmission connector shown in your picture. Tape off the end so it doesn't short.

I will bet that this is your fuse blowing problem. If the Solenoid is good, and your 4th pressure switch is still good..(It may not be as it was spiking current evrytime the fuse blew)...then things should work just fine with the pink wire cut off.

I'm afarid you inherited a bit of a mish mash...but certainly nothing that can't easily be fixed.

What happened is that at one point the previous owner changed the TCC from a dual wire to a single wire style. The dual wire style depends on applying a ground signal through teh 4th gear pressure switch..this is why there was a cut blue wire at the switch.

When they changed to a single wire solenoid..they forgot that the dash switch used ground to operate the old TCC...With teh new single wire solenoid, ground is internal...wire not needed....but it was still attached at pin D through teh dash! That is causing your short.

Just cut the pink wire...and your trouble will go away!

Vic
09-06-2011 07:19 PM
63ChevyII.com
Quote:
Originally Posted by cadmanof50s


BTW, if applying a +12volts at A or D gives a click, that means that the TCC solenoid negative terminal is internally connected to ground. This limits your choice of wiring somewhat....However, it is still a very workable the way it is.

Vic

I get a click when it is wired like this and I flip the switch:




If I want to bypass the mess of the spliced wires, can I just apply a +12volts to Pin A and not do anything with pin D? This would assume that the solenoid is internally grounded.
09-06-2011 07:08 PM
63ChevyII.com
Quote:
Originally Posted by cadmanof50s
What are you using PIN D for? Do you have a manual switch for towing? That is typically what this type of circuitry is used for.

Vic

The trans was pulled out of a '63 C-10, which I believe was used for towing.

There is a manual switch attached to the external wiring. Since I have this in my '63 Chevy II, I will not be towing with it.
09-06-2011 06:35 PM
cadmanof50s Sorry to be so long winded about this...but there is a complication with the wiring as it is.

Although it will work in theory, there is an issue which could be responsible for blowing your fuse.

They have the D pin wired to the signal that goes from the 4th gear switch to the solenoid. That means that when the 4th gear pressure switch is closed, voltage not only appears at the solenoid, it also appears on pin D. If the device connected at PIN D, is at ground signal (for whatever reason), then it will most definitely blow the fuse.

What are you using PIN D for? Do you have a manual switch for towing? That is typically what this type of circuitry is used for.

Vic
09-06-2011 06:18 PM
cadmanof50s There are several different ways to connect the internal wiring depending on what you want to accomplish. (Mine for example, only uses one wire signal to the transmission.) But that doesn't make mine right and yours wrong. It depend on what was the original intent.,

Before I answer your last question, however, do a simple test: By-pass the 4th gear pressure switch. Now see if the fuse still blows. If no, then your culprit is the pressure switch. Avoid driving around this way, though, as the TCC will lock up in any gear when there is voltage at A or D.

To answer you last question: The current wiring allows your car to automatically lock the TCC solenoid if there is voltage on PIN A AND you are in 4th gear.
However, IF you apply voltage to pin D then the TCC will lock also REGARDLESS if you are in 4th or not.

If you leave the wiring the way it is, it will operate as described above.

But keep in mind, that some installers want to engage the TCC by applying a ground signal as opposed to just applying 12 volts. Let me know what you want to accomplish and how..i.e. applying +12 volt to trigger or applying ground to trigger. Then I can show you how to wire it. BUT if it worked fine before and you just want to fix it, then teh wiring is fine.


BTW, if applying a +12volts at A or D gives a click, that means that the TCC solenoid negative terminal is internally connected to ground. This limits your choice of wiring somewhat....However, it is still a very workable the way it is.

Vic
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