OK I can't just sit idley by and not comment on this one.
I don't like to talk negative about anything but I have to here.
The wiring diagrams shown on this link.
http://www.700r4.com/tech/tcc/relay_install/diagram.shtmlhardly tell the whole story and look to be wrong.
First of all the diagram for the relay set up depicks only one of a possible 30+ different switching configurations inside the 700R4 can come in. I am sure that when one hooks up thier trany with this kit and can't get it to work ,the boys at the sales counter will gladly sell you the internal switch kit, that goes with it.
Don't swet it, it is easy to make the internal wiring right if yours is not correct.
In my GM service mannaul for the 1988 firebird there is 14 very different internal wiring configurations the 700R4 could have come in for that year alone. Some have solinoids that are internally grounded (grounded inside the pan to a valve body bolt) or some come extrnally grounded through the plug (like mine). Some have up to 4 oil preasure switches, and there are four types of switches used, some of those switches are "normally open" while some are "Normally closed" , they come in single post using thier case as ground or double post with no ground connection(mine was a wrong switch in the 4rth gear gallery which was the main reason my trany did not shift right). Other tranys could have one or more thermally activated switches wired in series or parrellel. Again this all depends on the set up it was configured to match the rest of the car that the trany came from.
The rest of your 700R4 is the same as all others, so all you will have to do if your trany is not right is remove the trany pan and change the switches as required, this may involve removing some exsisting switches and making sure the correct kind of switch is installed in the right port and that other ports where unneeded switches were removed are pluged. In some cases you may have to ground the solinoid black wire to a bolt inside the pan if it allready isn't that way.
On the brake light switch thing. It is not so clever and is to easy for anybody with half and elecrically inclined mind to think of this as the first and easiest way to make the TCC deactivate. But there is a reason the Feds told the car manufactures they had to use a seperate stan alone switch on the brake pedal. (it is just way too easy for GM to connect a simmular circuit to the exsisting brake light switch but they didn't!). The 1st problem comes in stopping the vehicle when the brake light switch fails to activate the relay, deactivating the TCC solinoid. If the TCC does not disengage while stopping it will be like trying to stop in a standard transmision vehicle without pushing in the clutch. (That is if your 700R4 is actually working right). Your trany will beet the S#*T out of itself as it downshiffs with the TCC fully engaged. Now I know stopping is kind of a new thing, not so well though out in the day of the early. That early brake light switch is about as reliable as my ex-wife. I installed an independant higher quality, weather protected switch to do the job in my van. Also if you have any elecrical screw ups with your brake light or turn signal circuit or your rear bulbs short causing the park lights to feed back through the brake light circuit, you are going to have a TCC clutch engaging and dis-engaging at will which I can garrantee will buger up your transmision if the TCC trys to engage at a very wrong time
I challenge any body out there with some elecrical knowlege to look at that schematic and guess whats going to happen when you are on the highway with the TCC engaged and you use your turn signal to change lanes ; HA HA HA!!!! Seriously, what are they thinking? Firstly the extra load of the primary coil in the relay will make a standard turn signal flasher goe high speed, and the TCC will go on/off/on/off/on/off with the flasher.
If you are using this relay in your van make sure the wire from terminal 85 of the relay gets connected to the brake light wire in your van that goes from your brake light switch up to the turn signal switch and not one of the brake light wires heading to the back. On the 1st gen that wire is the white one.
Now that "trailer towing hook up diagram" that is rediculas, let me explain, the intension of the extra switch is to shut off the TCC so it can't engage when you are heavy towing right? Firstly, in order for that TCC relay systen to work, the TCC solinoid has to be internally grounded and it gets its B+ signal via the red wire( the TCC is engaged when the solinoid is activated) which means the relay is a nomally closed relay (pins 87A and 30 are connected with brake light off) Power is at the 4rth gear preasure switch (which needs to be a normally open descreat switch which closes in fourth gear). Then only after you are in fourth gear the power will activate the TCC solinoid engaging the clutch. When power is applied to the primary side of the relay via the brake lights, the relay will pull and break the conection between pins 87a and 30 which will turn off the solinoid, dissengaging the TCC. Or if you down shift out of 4rth the presure switch will break power to the TCC and dissengage the clutch. Thats whats suposed to happen, so take a look at the added in switch on the blue wiire, what does it do? The only thing it can possibly achive the way it is shown is to bypass the 4rth gear preasure switch and allow the TCC to be engaged in any gear. Whats up with that??? That would be like up shifting a 4 speed standard trany all the way through the gears without using the clutch.
If you want to dissable the TCC for towing, you need the added switch to be on the red wire between pin 30 and the "key on wire" to cut B+ power.
Then on the other hand maybe I have it all wrong, maybe some one wants the TCC engaged more often when towing, but if so why in any/every gear?
It is a fact that both the trany and engine run a little cooler while crusing with the TCC engaged. But thats while crusing, not pulling a trailer up a hill. Most factory 700r4 set ups have other devises incorperated to dissengage the TCC when under heavier loads then cruise. The above aftermarket set up does not; unless you intend to add one (which is what the "towing switch" is for)
M1D
Last edited by m1dadio on Thu Feb 04, 2010 9:04 pm; edited 1 time in total (Reason for editing : wrong word used)
by Digz Mon Aug 24, 2009 7:28 pm
