[JackT]

The neutral safety switch on my transmission is the older single-pole type. Can I just change that out for the later three-pole switch or is there more to it than that?

[dave-r]

I think as long as you use the correct wiring it will be OK Jack. If you post a photo of it we can see if they are the same at the other end or not.

[JackT]

I believe I ordered a new one of the correct type for a 1970 727..... I'll compare and report back to you when I have both the single-pole and the three-pole switches in hand. The good new is that I have not put any fluid in the trans yet - it make dropping the pan a bit easier.

[dave-r]

Why drop the pan?

[JackT]

The switch isn't the problem. When they added the reverse light switch to the neutral safety switch (the two extra wires) they changed the cam that actuates the switch in the shifter. In the early shifters (1968 and before), there was a cam with two lobes, one for park and one for neutral, so you could start the car in either one of those gears. They added a third lobe to close the switch for the back-up light in reverse. They added this feature for the 69 model year. So, what I needs to have is a 1969 or later shifter in my 1970 car to get the reverse light working. I will check the wiring diagram to see what poles are the reverse switch in the neutral safety swich and check continuity in reverse before I get into anything further.

[JackT]

OK, so here are the results. I installed the new three-pole neutral safety switch after learning that the two outside terminals are for the back-up light circuit. I put the transmission in reverse and got continuity across those two poles. Just for grins, I put the trans in Park..... no continuity, so I do have the correct shifter in the tranny - case closed.

[dave-r]

That was useful information though Jack. Thanks.