Switch on the side of the 3 speed Muncie

[Buggalugs35]

I have searched and searched and cannot for the life of me find what the switch on the side of the Muncie 3 speed is. I thought it was the reverse light switch until I realized it is on the 2-3 shift shaft. I put a new switch in to wire it up and my reverse lights stay on unless I put the truck in 3rd gear.

The little black cable that goes to the switch runs along the bellhousing toward the passenger side of the truck

My granddad owned the truck before and moved the column shift to the floor and just painted the reverse lights red and hooked them to the brakes. I have been rewiring the truck and wanted to make them right.

It's a 71 350, any help would be much appreciated. My Chilton shows the switch but not what it goes too.

http://i50.photobucket.com/albums/f3...pste9owl4q.jpg

http://i50.photobucket.com/albums/f3...psn0ozqpdh.jpg

http://i50.photobucket.com/albums/f3...psdfphmn3q.jpg

[Boog]

Considering your truck is a 71 it could be that switch is part of the ESC circuit. That's ignition spark control that limits advance until the vehicle is in 3rd gear.
The backup light switch should be on the steering column inside.

[Buggalugs35]

Thanks that makes more sense.

If I switched to HEI with vacuum advance do i need that switch anymore?

[PatrickGMC70]

On my 70, it's TCS - transmission controlled spark. Someone who knows more than me can explain it better than I could. I think it's an emissions gizmo.

[Buggalugs35]

Thanks, I guess Ill just cap it off, i dont have any emissions controlling stuff hooked up.

[geezer#99]

It's a ground switch. Just leave it unplugged.
It was as said a tcs.
A solenoid that controlled when your vac pot got vacuum. THe solenoid had 12v to it with the ground switch on your tranny activated when in high gear.
Used on trucks mainly for ones that would haul heavy loads and needed more initial timing and couldn't use any extra timing from the vac advance until in high gear and cruising. Also used on some high perf cars that needed more timing on the bottom end for their increased compression.
You can run one with your hei as it's independant of your distributor.
And fwiw it wasn't an emissions device.

[scooterpimp]

Wow my 3 speed saginaw has the same deal. I was wondering why i couldnt get continuity in reverse. Well thats one more mystery wire i dont need to connect , now gotta figure something for reverse lights on floor shifter....

[Andy4639]

Originally Posted by scooterpimp

Wow my 3 speed saginaw has the same deal. I was wondering why i couldnt get continuity in reverse. Well thats one more mystery wire i dont need to connect , now gotta figure something for reverse lights on floor shifter....

Not knowing what floor shifter you have but I used a mini micro switch. Easy to hookup and you can buy different length arms on them.

[Buggalugs35]

Is anyone familiar with the hurst indy shifter and/or a reverse light switch to use for it? I really want to be able to have the lights come on without an extra switch.

[Buggalugs35]

On those micro switches what does the 3rd post go to?

[scooterpimp]

Originally Posted by Andy4639

Not knowing what floor shifter you have but I used a mini micro switch. Easy to hookup and you can buy different length arms on them.

Micro switch is the trick , i have access to alot of them , just gotta mount it to my hurst3 speed setup. Cool.

[Bigdav160]

And fwiw it wasn't an emissions device.

Sure it was. It altered the advance curve the the distributor to try and control HC/CO emissions. This system was eliminated when catalytic converters were implemented.

[geezer#99]

Originally Posted by Bigdav160

Sure it was. It altered the advance curve the the distributor to try and control HC/CO emissions. This system was eliminated when catalytic converters were implemented.

If so then why wasn't it standard equipment on all the motors?
And what about the trucks that still had them after the start of convertors.