I am converting my 70 Chevelle wagon from th350 to th400. can anyone help with the necessary wiring changes. I have the gas pedal bracket and switch already but what is the wiring differences.
To be "correct" I suppose you need a whole new wire harness. In real life, string a 16 gauge wire from an accessory terminal (powered with ignition on, unpowered otherwise) to the switch, then from the switch to the connector on the side of the trans. Tyrap as needed. Add plastic loom if you have any. Done. Easy.
Be sure to take the car out afterwards and test-abuse it many, many times. Gotta be sure the kickdown works, right?
IT'S THAT SIMPLE? WHAT ABOUT A RELAY ON THE FIREWALL? IS THAT FOR SOMETHING ELSE? IS THE TCS SOMETHING SEPERATE FROM THE TH400 KICKDOWN? MAYBE THE RELAY IS FOR THAT. THE WIREING DIAGRAMS ARE SO CONFUSING AND I'M A MECHANICAL ENGINEER!
I DON'T CARE ABOUT ORIGINALITY TOO MUCH IN THIS CASE.
SO WHAT I'M HEARING IS THE FOOT SWITCH GETS POWER ONLY WHEN THE IGNITION IS ON AND WHEN THE SWITCH IS CLOSED (WHEN ITS FLOORED) THE POWER GOES TO THE TRANSMITION. MY TRANS ONLY HAS ONE WIRE LUG ON IT SO THAT WOULD WORK.
A TH400 with TCS would have 2 connections. It looks like yours is not a TCS model, so other than finding a TCS model, it looks like its time to bypass your TCS. AND WE CAN ALL HEAR YOU...YOU DON"T HAVE TO SHOUT!
No. The TH350 does it kickdown via a cable which attaches to the throttle linkage at the carb. The TCS ( which stands for "Transmision Controlled Spark") is basically a sytem which blocks off the vacuum advance until your tranny is in third gear. The relay is for that system.
i prefer to shift if i want a downshift rather then to be surprised when it downshifts at times other than when i want it to( when wife is in car--- she goes nuts because she thinks im driving carelessly when it downshifts on hard acceleration)
the governor still shifts it down if i kick it below 45mph but above that its my choice to shift or not with the electrical disconnected
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