No Lockup

[Momar]

I just got the car recently, and the converter doesnt lock up. It is an 86 GN. I have already installed a trans cooler. The computer is telling it to lock. Do you think it would just be the solenoid, or how likely would it be that there is something major wrong?

Ben

 

[wagon]

Well, it could be a few things. Anywhere from minor to major.
First, make sure that the wires are plugged into the side of the tranny. Try pulling your brake pedal up just a little while cruising on the highway at a steady speed. The switch might be out of adjustment just enough to prevent lockup. If that doesn't work, then drop the pan and check to see that everything is plugged in. If it is, then you may have a bad solenoid. If that's not it, then it could be something in the tranny is messed up, or more likely, the tranny has been modified to run a non lockup converter, in which case you would have to replace the lockup valve in the valve body, and put a lockup converter back in.

Brian

 

[Momar]

Well, I will check on the other stuff, but one thing I can tell you is that the converter is still the D5.

As far as the brake, the computer is sending the signal to lock the converter(I used a snap on scan tool and checked this). Does the brake actually tell the computer what to do, or interupt the signal from the computer? If it sends a signal to the computer and the computer decides, then it is not the brake.

Thanks

Ben

 

[MeanBuicks]

The ECM provides a ground for the TCC circuit to lock when commanded. The brake switch makes/breaks the 12V supply to the circuit. It's possible that the computer is commanding lock-up but a lack of power via the brake switch would prevent the converter from locking.

You can probe the solenoid electrically from outside the pan by putting multimeter leads between terminals A & D on the case connector and measuring resistance. You should get around 25 ohms.

 

[turbowidow]

make sure the brake switch is making contact. i removed the cover on the switch and found the contacts were dirty, had to sand them with some fine sandpaper and adjust switch position.