(The white one )This part leaks transmission fluid when I back up, not when I drive forward. It screws into the side of my th350 trans. Is it a spark switch? is it a TCS switch? I have a used one, ( the black one) that screws into motor for oil pressure, but they are different! the white one I have that came out of trans has a tail after the threads, The extra oil pressure one ( black ) I have stops at the end of threads. The one I need has AC-20 on the side, but I can't find it on the web. any help out there where I can get one?

 

Yes, that is simply a line pressure switch used to activate the TCS. The GM part number is 6462514. If you search that number on Google, several originals come up, some at stupid prices. This one is $49. This is just a normally open switch that closes with oil pressure. Unfortunately, that is the opposite of how an oil light switch works, so you can't just use one of those. Or, you can delete the TCS and just run the distributor off of manifold vacuum. Put a pipe plug in the trans.

 

Wouldn't the same switch be used for the other gm cars, Buick, Pontiac, Chevy...

 

If you follow the link I provided above, it says the switch fits Pontiac, Chevy, Buick, and Olds. The problem is that apparently no one makes replacements.

 

Look at this one http://www.ebay.com/itm/70-71-72-OLD...38.m2548.l4275.

 

Thanks for the help. Maybe this is why my car didn't have the power to chirp the tires

 

Even a mid 70s Cutlass should be able to spin them. You may have to powerbrake more.

 

A bit confused. There are TH350 TCS switches being sold as replacements for the below applications, but some have the threads at the end of the switch, while others have a tail after the threads. Which is correct, and does it apply for the 1970 and 1971-72 applications?






4.057 ― SWITCH, TRANSMISSION CONTROL SPARK

1 6462655 1970 ALL TH350
1 6462514 1971-72 TH350