stock tranny locking & unlocking at cruise

[crownvic96]

i've been having a problem where at speed the t/c seems to lock and unlock randomly. i replaced the TCC solenoid with a new GM part and it is still doing it. what else could be causing a random unlock-relock of the torque converter?

the transmission and converter are stock. this is an '87 GN.

could the switch on the brake pedal cause this problem if it was bad? i did a vacuum swap a few months ago and the problem didn't seem to happen until after this.

 

[WE4]

TCC/Brake switch at the pedal.

Will cause this exact symptom. Look into it.

Bruce
WE4
www.PTSXTREME.com

 

[bison]

I have seen the brake switch at the pedal do this on 2 cars in the last few years. Check the wires going to it also. Many of these cars have had animals under the dash and the wires are a mess from their carelessness.

 

[EricB]

Do you have a aftermarket alarm???

GM had a TSB out for solid state alarm systems that would cause this problem also it would cause a slight miss fire and poor idle . being that you where under the dash you could have wiggled some of these wires loose. just a thought.

 

[crownvic96]

i replaced the brake and cruise switches and its still locking and unlocking above 45mph.

are there any other switches, connectors or sensors i need to check and/or test that tells the computer to lock/unlock the TCC?

i checked the connector at the transmission too. it looked ok. However the connector that comes out of the tranny can be rotated left or right a bit but doesn't have any in or out freeplay.

also if i get a chip made can i just have it programmed to keep the TC locked up over 45 regardless? i just ask this because i'm starting to get the feeling that this is going to be one of those mystery gremlins that'll drive me insane.

 

[crownvic96]

manually jumpered the aldl, when it unlocked ~55mph on the highway i connected the jumpers and it locked up no problem. what should i be looking at next?

 

[chris718]

what type of chip do you have?do you have a vss code stored in the computer?

 

[WE4]

If the fourth gear or third gear switch for that matter is bad and leaking it could do this also. I would drop pan and just replace the switches for giggles and test them to confirm. It wouldn't hurt to put two new switches in.

The other thing that could cause this , but is HIGHLY remote is the converter lock up clutch is just starting to fail. But again, highly remote.

Bruce
We4

 

[crownvic96]

lucky for me i have that blingtastic art carr pan with drain plug. guess i'll be putting it to good use sometime this week :smile:

 

[crownvic96]

do any of you have the part numbers for the third and 4th gear switches?

 

[WE4]

Not off the top of my head

I have the switches in stock tho.... 12.45 a switch. New design ones. But with the move, It will take me a little bit.


Bruce
WE4

 

[3.8TransAM]

If u have access to a Snap on 2500 u can watch it as it happens on the scanner.

Might be worth a shot to see which one is causing it if its on the trans end of things.

Had a friends 4th gear switch go bye bye causing this. Could see it flicker back and forth on the scanner.

later
Jeremy

 

[crownvic96]

I have the switches in stock tho.... 12.45 a switch. New design ones. But with the move, It will take me a little bit.


Bruce
WE4

cool, i'll give you a call in the next week or two.