gregsz-28

iTrader: (1)

By disconnecting the ECM and driving my car, will I damage my 700r4?

Also, I thought only one wire was required to operate a lock-up converter, but it seems that multiple wires go to the transmission, so, if I am right that there is more than one wire going to the transmission, (I didn't investigate much, or even go under the car and look), what do they all do?

RBob

iTrader: (1)

The only thing the ECM controls in the 700R4 is the TCC lockup. The other wires are for power to the TCC solenoid and the 4th gear switch back to the ECM.

Note that when the TCC is unlocked that the flow of ATF through the cooler is greatly reduced. On the early 700R4's the flow is actually stopped when the TCC is unlocked.

Best bet is to use one of the aftermarket TCC control setups for the lockup.

RBob.

gregsz-28

iTrader: (1)

Well that's a result I never would have guessed. With all the wires for the TCC lockup, can I make a manual switch for the converter? I don't plan on having this transmission for more than a few more months, so I'd prefer to not have to buy an aftermarket control setup for the lockup.

What's the '4th gear switch back to the ECM.'? What do I affect by disconnecting that?

Thanks for the answer, I thought I would have to 'bump' this thread a couple times...

mmadden55

I can answer some of that. The 4th gear is overdrive and the ECM shifts the car into it and out of it based on gear shift position and throtle position and the TV cable position etc. It is a nuisance really. Flat out on my GTA I get an overide on the overdrive which puts me back into third gear or I can back off the gas a little and go the same speed in overdrive annoys the heck out of me.

gregsz-28

iTrader: (1)

I know that 4th gear is overdrive,.

All 700r4's kick you out of overdrive past 1/3 throttle.
But, do you mean that mine won't do that with the ECM disconnected?
I drove my car just around the neighborhood real quick right after I disconnected the ECM to make sure all systems on the car still worked correctly, and it still shifts in to overdrive just fine, except my converter obviously doesn't lock up anymore.

So, in addition to my questions in post #3, how many wires go in to my transmission? And, can I make switches to manually control their operation?

chevyracingrox

how can you tell the tcc isn't working?

RBob

iTrader: (1)

You can place a switch to lock up the TCC. For short term it will work OK. Although it can get to be a pain. Which is why short term is OK.

The 700R4 won't lock up the TCC in 1st, nature of the beast. It is only capable of locking up in 2nd, 3rd, and 4th.

The 4th gear switch tells the ECM whether the trans is in 4th or one of the lower gears. This is the true gear, not the shift location. The ECM then adjusts the TCC lockup points accordingly. If you remove the ECM then the 4th gear switch doesn't matter.

Except that it can sometimes be used for auto-lockup once the trans reaches OD.

RBob.

gregsz-28

iTrader: (1)

, I'm not stupid.

RBob, I know the trans won't lock up in first, can you tell me what I need to do with the wires coming out of the trans to make a lockup switch? I only know how to do this using the ALDL connector.

g/f's z

sorry to hijack but is this gonna be the same story for my 83 with an 89 tranny and no ecm?

RBob

iTrader: (1)

Yes, power to the trans TCC solenoid is provided via the ignition and passes through a switch on the brake pedal. This ensures that the TCC is unlocked whenever the brake pedal is pushed. That all stays.

The TCC pin on the ALDL connector gets grounded to lock up the TCC. Just need to put a switch between that wire/pin and ground. Turning the switch on grounds the TCC solenoid activating it.

RBob.

gregsz-28

iTrader: (1)

I didn't think the ALDL connector would work with the ECM disconnected? I didn't look at the wiring that much though, but am I right?

RBob

iTrader: (1)

The ALDL connector pin for the TCC goes to both the ECM and the trans. Put another way, the ALDL pin doesn't tell the ECM to lockup the TCC. The TCC pin on the ALDL is the same wire that goes to the trans.

With or without the ECM tying that pin to ground will lock the TCC.

RBob.

geehumshriber

Hang on a second.

I just unplugged the TCC from the transmission this evening after having removed the ECM. The ALDL would obviously have to run through the ECM and THEN to the transmission.

Let's put it this way.

I've stripped out all of the wiring and the ECM from the vehicle. How do I wire up the TCC lockup switch now?

gregsz-28

iTrader: (1)

Those are the words I was trying to say!
I haven't tried to make my lockup switch yet, I haven't been driving very much anyways, been VERY busy lately.

geehumshriber

I've been using a diagram off of Autozone for removing the ECM. What I've noticed is that there exist a pair of plugs that feed somewhere to the drivers side of the vehicle. I sense that one of these is for the ALDL. Therefore, there is a continuation as the wires would go into the ECM and back out into the engine bay. From there it would extend to the transmission.

What I'm thinking of doing is wiring through the firewall on the drivers side from a button on the center console down to the transmission. My only issue then is, does the button need to connect to some sort of power source? I don't do much wiring so I have a hard time understanding how the lockup is "activated". What wire can I tap into (radio, ignition, ECM seeing as how it still has a fuse but is not really powering anything)? If it doesn't need a power source, there's actually a hole in my floorpan from the past owner that I could just drop the wire down through.

RBob

iTrader: (1)

Well, yes, if you remove all of the wiring then additional work will need to be done. But this isn't "disconnecting the ECM."

Grab the 4-pin connector that plugs into the transmission. Pins A & D are the two you want. The letters will be molded into the housing.

Pin A gets IGN+ power via the switch on the brake pedal. Pin D gets grounded to activate the lockup.

RBob.

davep_96

So are you saying that the ECM grounds the tcc, which activates it, but you can ground it manually via the ALDL?

Also, is there a way to make the aftermarket lockup harness at home so we don't have to spend a lot of money on some wires?

RBob

iTrader: (1)

Check these threads out:

https://www.thirdgen.org/forums/tran...-kickdown.html
https://www.thirdgen.org/forums/tran...up-tourqe.html

RBob.

g/f's z

http://cgi.ebay.com/ebaymotors/TCI-3...Q5fAccessories