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You heard me! I'm not talking about the TH200C (for the record, the "C" only denotes that there is communication with the onboard computer), I'm talking about a plain jane TH200 "Metric" which came with a non-computer controlled 1980 El Camino. If you think I'm smoking something, please check out the documentation posted here: Tech Area TH200 documents posting
On to business. I have a 1980 229 v6 Camino that has a TH200 "Metric". I'm planning to switch over to a 200-4R as seen in another thread (check out my .sig) Part of that switch over is planning for how to activate the lock up of the torque converter. I remember seeing some things in my engine bay that suggested this was planned for by GM, even before computers. Out of curiousity, I've tried the lock up converter test before (cruising at 55mph, holding accelerator and slightly touching the brakes to watch for a jump of about 200rpm on the tach) but I've not had any success.
I've noticed my emissions decal and what looks like an original installation in my engine bay:
Vacuum Hose/Emissions Decal on Radiator Support
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OEM Vacuum Switch Installation
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And this got me to wondering, how much do I need to purchase to get everything working for the 200-4R? So I set out to do some testing. The vacuum switch should be open (no connection) under low to no vacuum, but it should closed when manifold vacuum is high and constant (the delay check valve helps with consistency.) While checking this, I realized that my OEM setup is CONNECTED!!! There are wires that look OEM running into the fuse block. I took a quick look at the transmission and sure enough, there is a pigtail going in (remember, this is a NON-COMPUTER year):
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Getting excited, I took a look at to my brake pedal, and there was the special two-circuit brake switch (one is closed without pressing the pedal (TCC) and the other is open (Brake Lights). Wow! It's all there. Can it work? I decided to start testing to see what I could do.
I checked my OEM vac switch and found that under no vacuum it read a closed connection with relatively high resistance, which is very bad and needs a replacement:
Checking OEM Vacuum Switch
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I then checked the brake pedal switch. When the pedal is pressed, the TCC circuit should open and the Brake Lights closes. My brake lights work fine, so all I had to test was the TCC connections and all I could read was infinite with a few flickers of very very very high resistance. Checking the TCC circuit plug from the fuse block showed me that 12v was present with engine running. So, I opened up the switch to take a look and to see if it could be cleaned. Here is what I found:
Inside the dual circuit brake pedal switch
![]()
After cleaning/replacing these two things and cleaning the contacts of the connection in my engine bay, I took my Camino for a test drive. After attaining 55mph and a steady speed I tried the lock up test again. My first attempt didn't seem like anything happened, but I kept trying. Making sure I was in 3rd gear (this is the TH200 Metric we're talking about), holding 55mph with steady gas pedal pressure and tapping the brakes every-so-lightly I could SEE and FEEL my RPMs jump, exactly as they are supposed to with a lock up converter. I could feel the lurch as the RPMs jumped and also the softer clunk as that TC locked up again. It WORKS!!!
Long Story Short
Torque Converter Lock up was a factory option as early as 1980 (maybe even earlier, I'm only going by my empirical experiences) with the plain jane lowly 200 Metric. I know because I now have a working example!!!!
Please see the picture gallery of my 200-4R overhaul for more pics on getting the lock up functioning again:
> Gallery Here <
On to business. I have a 1980 229 v6 Camino that has a TH200 "Metric". I'm planning to switch over to a 200-4R as seen in another thread (check out my .sig) Part of that switch over is planning for how to activate the lock up of the torque converter. I remember seeing some things in my engine bay that suggested this was planned for by GM, even before computers. Out of curiousity, I've tried the lock up converter test before (cruising at 55mph, holding accelerator and slightly touching the brakes to watch for a jump of about 200rpm on the tach) but I've not had any success.
I've noticed my emissions decal and what looks like an original installation in my engine bay:
Vacuum Hose/Emissions Decal on Radiator Support
OEM Vacuum Switch Installation
And this got me to wondering, how much do I need to purchase to get everything working for the 200-4R? So I set out to do some testing. The vacuum switch should be open (no connection) under low to no vacuum, but it should closed when manifold vacuum is high and constant (the delay check valve helps with consistency.) While checking this, I realized that my OEM setup is CONNECTED!!! There are wires that look OEM running into the fuse block. I took a quick look at the transmission and sure enough, there is a pigtail going in (remember, this is a NON-COMPUTER year):
Getting excited, I took a look at to my brake pedal, and there was the special two-circuit brake switch (one is closed without pressing the pedal (TCC) and the other is open (Brake Lights). Wow! It's all there. Can it work? I decided to start testing to see what I could do.
I checked my OEM vac switch and found that under no vacuum it read a closed connection with relatively high resistance, which is very bad and needs a replacement:
Checking OEM Vacuum Switch
I then checked the brake pedal switch. When the pedal is pressed, the TCC circuit should open and the Brake Lights closes. My brake lights work fine, so all I had to test was the TCC connections and all I could read was infinite with a few flickers of very very very high resistance. Checking the TCC circuit plug from the fuse block showed me that 12v was present with engine running. So, I opened up the switch to take a look and to see if it could be cleaned. Here is what I found:
Inside the dual circuit brake pedal switch
After cleaning/replacing these two things and cleaning the contacts of the connection in my engine bay, I took my Camino for a test drive. After attaining 55mph and a steady speed I tried the lock up test again. My first attempt didn't seem like anything happened, but I kept trying. Making sure I was in 3rd gear (this is the TH200 Metric we're talking about), holding 55mph with steady gas pedal pressure and tapping the brakes every-so-lightly I could SEE and FEEL my RPMs jump, exactly as they are supposed to with a lock up converter. I could feel the lurch as the RPMs jumped and also the softer clunk as that TC locked up again. It WORKS!!!
Long Story Short
Torque Converter Lock up was a factory option as early as 1980 (maybe even earlier, I'm only going by my empirical experiences) with the plain jane lowly 200 Metric. I know because I now have a working example!!!!
Please see the picture gallery of my 200-4R overhaul for more pics on getting the lock up functioning again:
> Gallery Here <
