4L65E tranny question

[Lutronjim]

I installed a connect and cruise in my 70 Chev C10. It has LC9 engine and 4L65E tranny.

One of the wires in the harness goes to the brake switch to unlock the TCC which I have not hooked up. I have been told that 12v up the wire causes an unlock. Documentation states its for smoother operation.

As I understand it, the TCC will unlock when it down shifts out of 4th. Truck drives Ok in the test runs.

So question is, what good is it?

I do know some cars can test lock/unlock by lightly pressing brake at highway speeds which this hookup would do.

Thanks
lutronjim is online now Report Post

 

[Samuel6731]

If you dont unlock the converter while braking the motor will be trying to push through the brakes or make a early down shift affect sort of.


When that converter is locked it looks the motor and trans together so to say. What ever the motor does the trans does and the rear wheels do, by not unlocking for braking the tires are going to want to stay the same speed with the revs of the motor and the motor will remained revd.

All in all, just hook it up correctly! You're just going to eat brakes up and its not really ideal for the trans and motor anyway aswell.

 

[Lutronjim]

Thanks First answer I've had that makes sense.

I have searched this and several have stated that the PCM wants 12v on this wire to stay locked. The tech told me just the opposite - that 12 volts would unlock. Any ideas?