200 R4 something wrong and the trans shop didn't help

[needforspeed150]

My 87 GN has 30 K on the clock. All is good until everything warms up. Then the Transmission has been acting like it doesnt want to downshift when on the hwy etc and around town it acts like it is in to high a gear when going up a hill etc. I am not sure if this is the TCC or something else but took it to a local shop and I don't think they let it warm up. Told me couldn't find anything. Well I decided to put in a new TCC as the one in it is original. When I dropped the pan I found white wire and a green wire not hooked to anything. Shrink tubing has been put around the terminal. The Shop said they had done something and I guess this is it. I see a pressure switch that faces the back of the car that has nothing connected, I don't know what one that is. My question is where do the wires go originally. I have searched here and general searches and can't find where each wire should go. Also what was the Transmission guys idea in changing the wiring?
Right now they are as follows
White to nothing
Green to nothing
red to the two lug pressure switch and then to the TCC
Black to the TCC.
Other than when it warms up it acts fine and some places are rebuild happy and I would have to be convinced it is not just a small issue.
Any help would be appreciated
Ben

 

[machinegun]

So simple items you can do here.

First, get the car warmed up and drive I till the issue exhibits itself.

while the problem exists step on the brake while driving and see if the TCC unlocks.

If so then your TCC solenoid is usually OK.

Typically when I have seen TCC solenoid failure the car will act as if you did not depress the clutch when coming to a stop.

The wires, I have to verify but I believe the wires are as follows.

Black TCC solenoid to ECM

Red to the pressure switch and tcc solenoid

white and green are for 3rd and 4th gear signal to ECM.

Ill have to look harder for you to verify but I think that is right.

The ECM controls nothing to do with shifting, gear selection or pressure control of the trans. This is still done mechanically / Fluid control in the 200r4

 

[mikestertwo]

There should not be any "two lug pressure switch " in the transmission. There are 2 single lug pressure switches. The one pointed towards the back of the car is the 3rd gear status switch. The one pointed down is the 4th gear status switch. These are single lug N.C. pressure switches. The two wires from the TCC solenoid go directly to the connector on the side of the transmission. They are not supposed to go to any pressure switch. I can't imagine what the trans shop was trying to do when they changed the wiring. It almost sounds like they changed the wiring so the converter locks as soon as it shifts into 4th gear. Why?

 

[needforspeed150]

I took a couple pics Wish they were better. Maybe gives you a little bit more to go on.

 

[needforspeed150]

You can see the two wires unattached black and tan, the single lug switch has nothing on it. Then there is the two lug switch.. As the transmission has always been fine when not hot I can't think that it is much wrong but don't know what and my knowledge of automatics is limited.

 

[mikestertwo]

You can see the two wires unattached black and tan, the single lug switch has nothing on it. Then there is the two lug switch.. As the transmission has always been fine when not hot I can't think that it is much wrong but don't know what and my knowledge of automatics is limited.

I see what someone did. The stock chip used to lock the converter in 3rd gear. Someone rewired the trans so it would only lock in 4th gear. They replaced the 4th gear status switch with a 2 lug normally open switch. This way the trans would only lock in 4th gear. To put everything back to stock you have to replace the 2 lug switch with a single lug normally closed switch. Connect the white wire to the 4th gear status switch. Connect the green wire to the 3rd gear status switch. The two wires for the TCC solenoid should go straight to the side connector on the trans case. Tie the two red wires together that went to the two lug switch.

 

[mikestertwo]

I forgot to mention...replace the TCC solenoid.

 

[Sneezy6]

Could it be the over run clutches? I had a monte ss that would not downshift and die as I came to a stop after getting iff the express way. A shop by my house said that was the problem. He fixed it for like $200.

 

[needforspeed150]

Thanks for the input on this. I have something to go with now... As far as the forth gear only lockup as it is now. Do you think that is a good thing or not. In other words, should I change it back or leave it. That being said is the switch that I would need something that autoparts stores would carry?
I really appreciate the help on the crazyness.
Ben

 

[mikestertwo]

I would put the wiring back to stock . Modern chips like TurboTweak don't lock the converter in 3rd gear plus they need the 3rd and 4th gear status switches for other functions. Transmission supply houses should have the switches. Make sure it is a normally closed switch. What chip are you running in the car?

 

[David Husek]

My 87 GN has 30 K on the clock. All is good until everything warms up. Then the Transmission has been acting like it doesnt want to downshift when on the hwy etc and around town it acts like it is in to high a gear when going up a hill etc. I am not sure if this is the TCC or something else but took it to a local shop and I don't think they let it warm up. Told me couldn't find anything. Well I decided to put in a new TCC as the one in it is original. When I dropped the pan I found white wire and a green wire not hooked to anything. Shrink tubing has been put around the terminal. The Shop said they had done something and I guess this is it. I see a pressure switch that faces the back of the car that has nothing connected, I don't know what one that is. My question is where do the wires go originally. I have searched here and general searches and can't find where each wire should go. Also what was the Transmission guys idea in changing the wiring?
Right now they are as follows
White to nothing
Green to nothing
red to the two lug pressure switch and then to the TCC
Black to the TCC.
Other than when it warms up it acts fine and some places are rebuild happy and I would have to be convinced it is not just a small issue.
Any help would be appreciated
Ben

Hi Ben, The mods done should make it lock up when in fourth only. Not correct for a Turbo Buick. I suggest getting a new harness instead of fixing the one you have as it is cut too short now. Get a new TCC solenoid and pressure switch to go back to stock. The computer uses these switches for signal of 3rd and 4th gear. The switch is normally closed.

Green Wire - 3rd pressure switch - faces rear of car
Tan Wire - 4th pressure switch - faces the floor
Red Wire - 12V to TCC Solenoid
Black Wire - GND from computer to TCC Solenoid

Since the main problem here is happening when hot it is likely that the TCC solenoid is bad. To determine this, disconnect the plug on side of the case when cold. Drive the car to hot and see if problem is gone. Either way put back to stock. If you need help when doing this check, contact me

 

[needforspeed150]

Thanks for all of the input. The transmission is perfect now. Two new switches and a solenoid . Ok Now I'm wanting to upgrade the ol' beast.