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Overdrive wiring question


Senior Member
I am trying to hook up all the wiring on a partly restored 74 1/2 TR6 I picked up. I am confused about the wires that go to the overdrive. There are four female connectors (black and taped together) that seem like they should go to the two switches on top. However, the lead to the solenoid has four female connectors (white) in series on that single wire.
Can anyone explain where these go, is something there that shouldn't be, or am I just screwed up? The book doesn't give me a clear layout of these wires.


Great Pumpkin - R.I.P
Is this a J-type OD, or A-type?

Normally a J-type would have only one switch on the top cover for the OD; but there could be other switches for the backup lights and starter interlock. The solenoid would have just a simple wire from one terminal of the switch on the top cover, and another wire from the other terminal to ground.

I'm afraid I don't understand your comment about four female connectors in series.

The wiring diagrams at https://www.advanceautowire.com/schematics.htm are generally considered to be the best. The books frequently don't cover all the variations (especially in US-spec cars).


Senior Member
First, it is a "J".
I was looking at it again and am thinking that the black connectors may not even go to the trans. The connectors on the single wire to the solenoid may be for the trans. switches. They were all together with a wire tie.

If that is correct, then I need to find a home for the black connectors.

Still confused!


Jedi Trainee
hondo402000 said:
yours is a lot more complicated than my 71 model, you should get a wiring diagram for your year


Yea, I second that.

The TR4's, TR4A's, TR250's and early TR6's are easy. The late ones get tough.


Country flag
+1 on Advance diagrams.

The wiring isn't that hard. Sometimes it is helpful to pull everything off and put it all back together correctly.


Senior Member
I checked the wiring diagram and the OD is the Yellow/Green wire I'm looking at. The two switches on top of the shifter activate second gear OD and third/fourth OD. The single wire in a series configuration would allow the solenoid to activate from either switch. Checked the switches and found they are both bad but was able to feel movement of the selector rods through the holes.


Great Pumpkin - R.I.P
The J-type should only be active in 3rd & 4th gear, so it takes only one switch on top of the shifter. You must be looking at a wiring diagram for an earlier car.


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