4l80e 4th gear and tcc problem (running from 4L60E segment)

[joecar]

Updated Summary post #26.

[slow67]

Thanks Taz. That did occur to me, which is why I would run the PWM through the relay, meaning, the PWM is not activating the relay, the relay is simply conducting the PWM signal between the controller and the transmission. The on/off signal on the other hand is what energizes the relay.

The PWM signal will only energize the TCC solenoid inside the transmission, but only if the TCC on/off signal is on.

Like this:
Attachment 12063

It will work fine

[GNXClone]

Alternative (see posts #27 and #29 below, thanks GNXClone/Mike):
use the 4L60E TCC ON/OFF signal to drive a relay to gate the 4L60E TCC PWM signal to the 4L80E TCC PWM solenoid:

Attachment 12216

(see post #29 below)


Note:
The F-car 4L60E segment keeps the TCC locked on closed throttle decel (until vss goes below the unlock curve).
The Truck 4L80E segment (there are no car segments) unlocks the TCC on close throttle.

This TCC relay scheme works great by the way. I have now tested it. The only thing I had to do was add a 100ohm 10W resistor so that when the TCC is disabled, the TCM will still detect a solenoid is present (really a resistor).

[joecar]

Mike, where did you put that resistor...?

[GNXClone]

Mike, where did you put that resistor...?

The resistor is placed between the previously unconnected relay terminal and +12v so that when the TCC enable is off, the TCM will still detect what it thinks is a solenoid. By my calculations, a 2 watt resistor would work, but Radio Shack carries the 100ohm/10watt in stores and its not a bad idea to use a higher rating here.

And I must say, PWM lockup is so much smoother than ON/OFF.

I also attached a photo of the adapter board. This has since been wrapped up in black electrical tape and looks like it's part of the harness. There's the Shift Solenoid B inverter relay, the TCC relay, the "fake" 3-2 shift solenoid resistor and the "fake" TCC PWM solenoid resistor for when TCC enable is off.

[joecar]

Cool thanks for the pic.