Forth Gear Switch ?????

[N2TURBO]

Quick question, just bought a 86 T TYPE.Hooked up the turbolink and the third & forth gear is on.But the car is idling in park is this correct ???????

 

[MeanBuicks]

Look underneath the car and see if the four-terminal wiring harness is hooked up to the driver side of the transmission. If it is, either the internal harness is disconnected or missing altogether.

Perhaps someone converted the transmission to a non lock-up?

 

[N2TURBO]

Here's the scoop,i know the complete history of the car so no mods were made.The trans was just rebuilt a year ago,so im thinking they didnt connect something inside the trans.All the connections are good on the outside.The converter locks up?What tells the computer when it is in third & forth gear?????Is there a third & forth gear switch? Trying to learn from this experience. THANKS!!!!

 

[Sleeper]

The pressure switches are on the bottom of the valve body. If you pull the pan (and filter) you will see two round switches hopefully with single wires coming off each of them, that go to the connector on the side of the case.They are NC, (normally closed) so if you have a wiring problem or bad switch they will show "on" on the Scanmaster.

HTH
Paul

 

[Brian Harper]

By normally closed, do you mean they will open when the trans goes into 3rd or 4th gear or close? Also, do they go to ground when closed? I'm trying to troubleshoot a problem with my transmission - the TCC locks up as soon as the tranny shifts into 2nd gear, making me think I have a bad 3rd or 4th gear switch or a wiring problem, but I need to figure out with way they are wired so I can troubleshoot.

 

[MeanBuicks]

Brian,

It means that the switch is grounded until pressurized; then it opens. If your converter locks immediately, your solenoid is most likely the culprit. Luckily it's easy to replace.

The pressure switches won't cause that to happen regardless of their situation.

 

[Brian Harper]

Thanks Greg.
Actually, I just had the TCC solenoid replaced, and it now passes the brake pedal test ok (even in 2nd gear), so I'm confident that it's working ok. Kick me if I'm wrong, but the way I see it the ECM sends the signal to lock up the convertor when it sees the tranny in 3rd or 4th gear via an open pressure switch contact. If I had a bad connection the ECM would always see the open switch and lock up the convertor, unless the brake pedal is touched. Does this sound right to you?

 

[MeanBuicks]

The pressure switches do factor into the equation as to when lock-up should occur but so does TPS and vehicle speed. Having open switches still shouldn't make it go to lock-up immediately after hitting second gear. Does it lock-up regardless of your throttle postion or speed?

 

[Brian Harper]

Does it lock-up regardless of your throttle postion or speed?

Yes. Even with extremely light throttle, right after the car shifts to 2nd the converter locks up. If I lightly touch the brakes it will unlock until I take my foot back off the brake pedal, then it will lock up again.