Hello All,

Once again I turn to the gurus. Here's my dilemma. I had this switch go bad. ( it took me 3 trans pan gaskets, a front seal, a rear seal and some new fittings to find it, but I am now a better person because of it . It blew trans fluid everywhere only in Drive and especially in Reverse, but was in the corner and looked like a warped pan, etc. I put a plug in it instead the first time and left the wire unplugged of course. I noticed the car would lurch sometimes (like a plug wire was arcing) and put 2 and 2 together that it must be connected in some way. So I bought a new one on ebay. Lasted about 6 months and then the same thing happened where it blows transmission fluid out of the backside of the sensor where the electrical spade is. By this time I have almost lost a transmission 2x and am done with this inferior design. I filled the thing with fluid a bunch to get home and no real damage has been felt yet. My issue is I want to permanently leave the plug in and want to know what I need to do to eliminate the lurching,etc. Do I raise timing? I'm @12* now with HEI, Edelbrock intake, rebuilt qjet. Any help would be greatly appreciated. I have included a pic of what I was running in there from ebay. I'm sure it's a TCS and I see the vacuum lines going to a splitter where the carb, manifold, dist. etc. vacuum lines all meet up. with wiring on the top. I'm pretty sure that's where the wire goes on the manifold but I haven't been up to the car in a few days.

 

It's not the TCS switch. TCS is located on the front of the intake manifold on 71/72 olds engines.

 

So just connect your distributor vacuum advance to either the ported vacuum barb on the carburetor, or to manifold vacuum (whichever works best for you), recheck your timing, and be done with it.

Have you adjusted your HEI distributor for use in your '72 engine? If not, that would probably help as well.
There are many threads here and elsewhere that go into this.

- Eric

 

@allen R. Thanks for the clarification. I was wondering does this pressure switch on the outside of the transmission send a signal to open the TCS switch allowing vacuum to the distributor? I'm thinking it does but am not sure. Excuse my ignorance but I am a diesel guy! Eric, car runs awesome with the HEI, I put in a pertronix coil in cap unit, NGK plugs gapped larger, and 12* timing. Engine has about 3k on a rebuild. It only does this when I remove the transmission switch and replace it with a brass plug. It's on the passenger side front of trans. (forgot to mention it is a CA car so i'm sure it was an early BS smog device.) Only ? i have is that there are 2-3 other vacuum lines on this TCS switch on the manifold. Can I plug the one that goes to the distributor on the switch itself and then do as you recommended and hook it to a carb vacuum or manifold vaccum so that the others operate correctly. I believe one is from carb and the other? Again I'll go out to the car this weekend but just wanted an idea of what i'm working with. Thanks as always guys!!

 

Just get a piece of vacuum hose and connect the advance canister to the vacuum source of your choice (ported or manifold).

If any of the hoses to the TCS are still connected to live vacuum sources, remove them and plug the sources.

You can remove the TCS or leave it - your choice.

You would benefit by reading the page in the Chassis Service Manual about the TCS in the Emissions chapter.

- Eric

 

 

Got it! I'll check out the manual, definitely one of the best investments I've made! I just go to you guys for knowledge as the manual didn't quite have any info on HEI, Edelbrock manifolds or roller rockers! Thanks and have a great weekend!