My neighbor is a transmission guy and warned me about the temperature switch failure (recommending bypassing it).

Connecting those two wires together bypassed the temperature switch, completed the circuit, and my convertor lock-up became functional!

These two wires went to either side of the temperature switch. I assume the other two are for diagnostic purposes. Remember above when I said I had a 'theoretical' one wire setup? Well that is because I actually have three wires going to the transmission. It only seems applicable to very cold areas of the country. From what I read the setting is not that high. It is there to avoid convertor lock up until fluid temperatures are optimal. My transmission had a temperature switch between the grounding pressure switch and the negative side of the lock-up solenoid. Regardless, I also have a switch on the 12V+ side so at my choosing I can deactivate the convertor lock-up.ģ. It is actually a pressure switch in the 4th gear fluid circuit that closes the negative side of the lock-up solenoid to ground (making it active) and engages the convertor lock-up. While it is necessary, the 12V+ runs directly to the positive side of the lock-up solenoid. Many would think the 12V+ is what is switched to engage the convertor lock-up. So, make sure this information is applicable to your type of 700R4 (again mine was a '92 version).Ģ. The 700R4 had many valve body configurations. In the hope of having others avoid issues I had, I'm relaying the following information:ġ. That being all one had to do is run 12V+ to the transmission and as it shifted into 4th gear (OD) the convertor would lock up. Thankfully the advancement of the '92 version of the 700R4 already had mine as a theoretical 'one wire' set-up. My 700R4 was sourced from a '92 Buick Roadmaster (with Chevy 350 engine). In case anyone is doing a 700R4 conversion I thought I'd throw this out there.

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