4 speed switch

[hemigtx]

Here's one for you. The 4 spd in my 72 340 RR never quite shifted right, and I grew weary of leaving a trail of gear lube everywhere I went so I rebuilt the thing this weekend. The lube was leaking from, appropriately, the "emissions switch" on the inspection cover. Apparently, this was a one year deal. There was a green wire that connected to the thing until I ran over a road alligator (retread) which wiped it out. The now broken emissions switch emits gear lube. It is doing a wonderful job of preserving the underside of the car, but other than that it generally pisses me off. Well, two trips to the dealership netted me a back-up light switch. Chrysler has superseded the emissions switch with the back-up switch which doesn't even fit due to a smaller diameter. Napa doesn't list it either. I brought in the broken one which has a number on it, but they were unable to cross-reference it. Has anyone seen one of these beasties? Does anyone know what it actually DOES? I'm just going to plug the hole off, but I was curious about it's utility. It doesn't appear to affect anything...
Semper Fi

[TL]

I think it prevents spark advance until you are in high gear.