How to replace 700R4 TC Solenoid?

[bobss396]

I have an '84 Caprice with the 700R4 tranny. The transmission control solenoid is unplugged, I'd suspect that it is bad. NAPA has two of them for like $31.

How do I know which one I need? One is computer grounded, the other is self grounded. There is a color difference on the coil insulator, one is red the other is black. Is this visible from outside the tranny?

Also how hard is it to install? I should have everything I need to drop the pan and install it, but would like to know how much of a task it is before I drop the pan.

Thanks, Bob

[silicon212]

Transmission Control solenoid? You mean TCC Solenoid? That's Torque Converter Clutch.

It's the only solenoid that will be in your transmission.

First, you will have to jack up the car and drain the oil from the tranny, then remove the pan. Remove the filter. Usually the O-ring for the filter sticks into the front pump, if this is the case you will have to fish it out. There will be one or two pressure switches on the back of the valve body (TH700 for '84 is supposed to have one, but I've worked on an '84 Caprice TH700R4 - it had both). One has one wire connecting to it and the other has two. The wires run along the valve body to the front of the transmission (note the position of these wires along the valve body, you will be taking these off and putting them back on) - this is the location of the solenoid (it plugs directly into the front pump). Two 10-mm head bolts hold it on - remove the bolts and pull the old solenoid straight out. Lubricate the o-ring on the new one with some tranny fluid (there should be plenty dripping off of the valve body you can use, lol) and plug it into the hole in the same orientation. Replace the two bolts and re-route the wires along the bottom of the valve body, plugging them back into the pressure switches at the back. Install a new filter and a new gasket and put the pan back on, throw in 3-4 quarts of fluid (don't overfill) and you should be back in business.

[bobss396]

Thanks for the fast reply. Is the outside tranny plug part of the new solenoid assembly? The picture from NAPA shows that it has one, or is the solenoid a purely internal part? I was wondering how the plug would pass through the case.

Bob

[silicon212]

The case plug is a plug on both sides - the wires for the solenoid plug into it from within the transmission. Sometimes you get a new plug with the solenoid - in this case, you only have to remove the plug (it clips on from within). The solenoid itself is completely contained within the transmission.

[bobss396]

Thanks, I figured it had to be easy one way or the other. Once I have it apart it should be more obvious I'm sure. The car is overdue for a fluid and filter change anyway.

Bob

[400wagon]

Have you tried just plugging it back in and seeing if it works. If the wiring is bad you can wire a switch up to lock it up manually. It may be the wiring itself and not the solenoid inside the transmission

[mackamitsu]

Originally Posted by 400wagon

Have you tried just plugging it back in and seeing if it works. If the wiring is bad you can wire a switch up to lock it up manually. It may be the wiring itself and not the solenoid inside the transmission

so you could actually test the solenoid by shooting 12V directly to it. If it clicks, that means it is a wiring issue not the actual solenoid.

[400wagon]

here's a page with some info on the 700r4 and wiring
http://purplesagetradingpost.com/sum...o/700R4p1.html
I used a few of these diagrams to wire up a switch in my dash to manually control the tcc. There are three prongs on the wiring, B, A, and D. A gets 12v, and B or D get grounded to make the tcc engage the lockup. I wired mine like the diagram at the very bottom of the page, but either way you flip the switch will lock up the converter no matter what gear you are in (except 1st), but I don't know if that's a problem with the diagram or with my car itself. Lockup isn't useful in 2 or 3rd gear anyway.