Gathering info stage: Wanted to know how A904/727 circuit that operates the lockup TC by how? By pressure of what? So on.

Reason I ask is I wish to see if I could create a electronic circuit to "monitor" a A413 via the test ports (this is mopar FWD 3 speed transmission, many of them have electronic TC lock up) because I run carb 2.2 and computer does not have lockup provision and when I go injected, will be megasquirt, from what I see might still have no support for lockup.

I lose some speed uphill if I hold steady on throttle if 50Km/h or under. If over 60Km/h the TC slip is less. But this long uphill road is in 50Km/h zone. So this either I lose speed down to 40km/h or lose mpg by applying more throttle. :p

Trying to improve MPG.

Cheers & thanks, Wizard

I dont know how the FWD ones work but the 904ish trany that was in my 1991 D150 would lock up when it was told to by the computer. If you put 12volts to the TC connecter on the trany AND it was in 3rd gear it would lockup. In kickdown or 1'st or 2nd it wouldnt lock up no matter what the voltage was at that connector.

If yours works the same then you could wire a little override switch to force it to lockup at lower speeds in 3rd.

Thanks for the reply.

The original quest still remains. Need to see the A904/727 theory of operation or someone to talk about this lockup, particlarly the area circuit that determines lock up to be active or not.

Cheers, Wizard

I guess you could have constant 12volts to the lock up connector. When its in 1st or 2nd it would be over ridden and not lock up. As soon as it gets to 3rd it will lockup. Then put a switch on the TPS that will brake the 12volt connection when you are at WOT or near WOT.

Duno if that woud mess things up. Just tossing idea's out there.

I would like to know how one could disengage a 904A's lockup electronicly? Maybe add a hydrolic switch some where. My understanding is that lockups are a failure point in high HP applications. If we could figure out how to unlock it with anything say, over half throttle, it would seem to me that the failures would stop. Keep in mind the this transmission has not electical input regarding the lockup system.

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