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I have looked all over and I cannot find out what this bolt with a plug coming out of it is. This is a Muncie m20 oringinal to my 72. Does anyone know what this is for.
I believe that is for the high-range switch used in the T.C.S. system (transmission controlled spark). It was an emissions control strategy used for a couple of years on base engines [eliminated the need for the A.I.R. pump stuff].
When in high gear (or maybe 3 & 4 with the 4-speed), that switch would allow manifold vacuum to be applied to the distributor vacuum advance can. In low ranges vacuum advance was defeated.
I believe that is for the high-range switch used in the T.C.S. system (transmission controlled spark). It was an emissions control strategy used for a couple of years on base engines [eliminated the need for the A.I.R. pump stuff].
When in high gear (or maybe 3 & 4 with the 4-speed), that switch would allow manifold vacuum to be applied to the distributor vacuum advance can. In low ranges vacuum advance was defeated.
What he said.
Mine still has the thermostat but the electrical connection is disconnected as I'm not using TCS.
Solution to permanently delete the TCS and stop the leak would be to figure out exactly what thread the hole in the trans side cover is and install a proper plug, making sure the plug does not seat so deep it locks the 3-4 shift fork shaft.
4 Speed question
