I'm looking at a 4T60 swap following information here: http://www.spacecoastfieros.../440-4T60/index.html

Scroll right to the bottom of the file to "Torque Converter Clutch (TCC)".

Has anyone else added this second relay he's described? Any difference in running with or without this thing?

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3.4L S/C 87 GT www.fierosound.com
2002/2003/2004 World of Wheels Winner &
Multiple IASCA Stereo Award Winner

The trans shop that rebuilt my trans gave me a 55 psi switch to screw in where the pipe plug is under the governer. Then I spliced it into the the tan and black wire from the tcc plug. It works normal and is alot easier to do. At 55 mph the governer pressure is 55 psi and at that piont the lock-up kicks in. And when you step on the brake it goes off. Hope this helps.

Joe

quote Originally posted by GODFATHER: The trans shop that rebuilt my trans gave me a 55 psi switch to screw in where the pipe plug is under the governer.... Hope this helps. Joe

It sounds like the ECM is no longer in play with this setup.
More details would be helpful - switch part number, wiring sketch, any pictures?

[This message has been edited by fierosound (edited 11-14-2007).]

Godfather has a 4T60 not the 4T60E. The E trans is controlled by the computer.

quote Originally posted by foxgapfiero: Godfather has a 4T60 not the 4T60E. The E trans is controlled by the computer.

Even the 4T60 normally has ECM control for TCC lockup. Shift points and firmness are controlled by the TV cable and modulator respectively. With the 4T60E the ECM controls everything.

So with this switch on his 4T60 it sounds like he's bypassing the ECM controlling TCC lockup.

I have a carb. sbc so the computor is not used. The tcc is wired to the pressure switch. Here's what I was talking about. Sorry I don't have a part # on the switch. It looks like a regulor pressure switch. Try and call a trans shop and ask them.

This must be the kind of thing your transmission shop gave you.
I'm not clear on where you installed it. Where is the 4th gear test port?

http://www.transmissionpart..._p/480-000048388.htm

[This message has been edited by fierosound (edited 11-19-2007).]

^^^

Yep. That looks like it. Pics are not showing up for some reason on this trend. The port is right under the governor and by the r/s axle. It's a 1/8 pipe plug. The original plug for the tcc on the th125 trans has a purple wire and a tan and black. The purple wire has power to it when the key is on and when you step on the brake the power is interrupted (off ) and the tcc disengages. The tan and black wire gets cut and you splice it into the switch. So you cut the wire about 3 inches away from the plug and run one section from the plug down to the switch and then run another wire from the other side of the switch back up to the tan and black wire you cut. When the pressure at the switch reach 55 psi it grounds the circut and engages the tcc since theres power to it all the time from the purple wire. At the port under the governor 55 psi is approximately 55 mph. And if you step on the brake the power goes off and the tcc disengages.

Joe

Best explanation I have found of electrical/vacuum control and electronic control of TCC: http://www.geocities.com/va...nsmission.htm#torque

This is the 125C tranny (4t60 is similar), but the port by the governor is #119 in this diagram

[This message has been edited by fierosound (edited 11-19-2007).]

119 is the plug where you put the switch. I put a 90 degree elbow and screw the switch into it for frame clearance. It works fine I have no problems with with the tcc working properly. If I gently step on the brake pedal you can see the rpm's go up and you can feel the tcc disengaging. I just drove the car from PA to SC almost 800 miles with no problems. Sometimes we tend to over think things when something seems to easy . The 4t60 is controled by vacuum for its shift points. The TV cable is only for passing gear, the onlly electrical part in the 4t60 is the TCC . The 125 uses the TV cable for its shift points and other variables for the TCC to kick in.

Joe

[This message has been edited by GODFATHER (edited 11-19-2007).]

thank you for posting some more info on this ,does anyone have any input on the question of the drawbacks of not hooking this up with a carbed engine ...thanks

anybody?

quote Originally posted by tfwcars: thank you for posting some more info on this ,does anyone have any input on the question of the drawbacks of not hooking this up with a carbed engine ...thanks

My manual is NOT clear on exactly how the ECM control TCC lockup. One one page it says it needs Brake off, VSS, TPS, MAP and Engine temp inputs while another page in the same manual doesn't list the MAP sensor as a required input. Anyway, if any input is missing or sensor is bad the ECM won't work it properly.

In a carb'd application, if the ECM is still in the car, adding the required sensors will allow you to use the ECM to control TCC lockup. If the ECM is scrapped you need mechanical control of TCC lockup. It can be done as above with a pressure switch and kits can be purchased from Jegs/Summit for vacuum control of the TCC lockup. In any event it is something that would be good to get functioning properly. With highway cruising, it lowers engine RPM and saves gas.

The general consensus of running a modern transmission WITHOUT a working TTC lockup is that it will reduce your gas mileage, increase transmission oil heat and shorten transmission life. http://www.technicalevolution.com/tcc.htm

[This message has been edited by fierosound (edited 12-03-2007).]