ToniJ1960

I tried for an hour to search for this transistor and cable assembly.


the white connector is the new pigtail to be installed at the trans. The other end with the black connector has the transistor soldered in.

The white connector will fit properly it seems into the old connector at the other end that's why I assume another pigtail exactly the same will fix that end.

ToniJ1960

car side of cable with transistor



melted on something but probably servicable

Gibbles

You need to see someone that knows transmissions.
run the car on a lift, connect a gauge to the pressure ports.,.
The servo on the right side of the case has two pistons in there, the one inside the cover is the actual 4th servo.
It pushes on a pin, that closes a big band that's used for both second and 4th...

otherwise it may end up being in the valve body, or further in.
also, on my transmission, if i have my tv cable to tight, i don't get 4th until something like 70mph, however I'm npt sure if that's related to my shift kit...

confab

He's wrong.

JoBy

This is the shifter on my "early" (#902) 1984.



And this is the newer with [D] and D

ToniJ1960

I have the early one

he also thinks this cable piece might be an aftermarket lockup controller. red black and white wires doesn't look to be correct for my 84 tcc. he could be right on that has anyone here seen this part before, should there be only one connector between the ecm/brake switch and the tcc at the trans? This just got stuck in between by someone at some point?

ToniJ1960

Can anyone identify this cable in post 23 thank you

JoBy

ToniJ1960

thank you trying to figure out if this cable should go back in or not

confab

It looks like it fits the case connector. It'll run the lockup clutch.

ToniJ1960

its a little weird to see a transistor or scr or whatever it is in there isn't it? Maybe its a lockup controller?

confab

It could be a diode. The TCC solenoid is supposed to have a diode on it.

But that's all it runs is the TCC clutch. No other solenoids in a 700.

ToniJ1960

Its a TO 220 I would bet its a transistor, and I never saw a transistor or an scr in the diagrams we all see.

The diode across the coil is just an emf suppressor for the flyback voltage across the coil. The diode is placed across the coil reverse biased so it wont affect the current through the coil, but it will break down or conduct at a certain voltage point. It just breaks down and conducts to protect the coil or transistor or whatever from the flyback that would be produced (high voltage from collapsing current/field).

Im sure its mounted right at the solenoid terminals.

This guy who looked at the transmission said he thinks it could be a controller for the lockup maybe aftermarket. He could be right Im leaning towards leaving it out right now at least.

confab

The diode is a flyback diode, yes.. But there's nothing there that needs a transistor.

You could pull the pan and see if they did anything, I guess..

ToniJ1960

There might be a normally closed (instead of N.O. 4th gear switch used on some controller kits I read.

The transistor might operate with the emitter or the base grounded (or connected to the 4th gear switch?) and act like a switch to control some (usually) larger current. So if its in 4th gear and the switch is closed the emmiter is at ground and it switches the transistor on. I haven't worked it out yet on paper but it seems pretty likely. It could be PNP even.

confab

It's a series thing in the early units. Not nearly that complicated.

No reason other than some wild upgrade for it.

WVZR-1

OP - Do you actually know that the transmission is original to the car? Should be a code on the case rail that might ID at least the case origin.

Maybe this is a 700R4 that was originally in a truck, van or whatever, maybe gas or even diesel

ToniJ1960

I will try to find that code