Wiring 3 prong overdrive plug
If you route either a pressure or manual switch through the same contacts as you have your OD on, it could lead to unpredictable operation. What you would need is a double pole, single throw switch ( DPST ) where one set of contacts routed the OD and the other routed the TCLU. That way, when you manually locked out OD, the TCLU would follow.
It should start off in 1st even without the O/D hooked up. You probably have a governor valve sticking. But I have to ask why did you have the O/D hooked up to a switch to begin with?
I bought it that way. I don't know why it was like that. The 2 prong overdrive plug just hangs there. Maybe I'll call the trans shop about it not starting in 1st with out overdrive hooked up. That is just what they told me
If the trans shop told you that they are wrong. Does it start off in first gear if you put it in neutral and then back to drive? If it does but doesn't down shift back to first after coming to a stop then most likely a governor valve is sticking, pretty common. If it never starts off in first after being put into drive from park or neutral then there are other problems.
I'd pick up the A21 switched power circuit, available at the grid heater relays. Dark blue wire to a coil terminal. If the grid heater relays have been deleted, pick up the circuit at the ASD relay, same color.
Follow the blue wire. It would be on one of the smaller studs. Check it with a test light. Should have power when the ignition switch is on.


