200-4R TC Lockup Kit - build your own

[ssn696]

I bought a 700-R4 lockup kit a while back. It uses a pressure switch that closes a circuit that applies current to the TC solenoid when it senses pressure on the 4th gear circuit. I would like to see if I can make this kit work on a 200-4R. The expensive 200-4R lockup kits put a switch on the 4th gear pressure channel on the valve body, inside the pan. Is there an external 4th gear pressure tap on the 200-4R? The 700-R4 4th tap is behind and below the 2-4 servo, although the later ones lack this and one is supposed to drill and tap the servo cover for 4th line pressure.

Thanks for any advice.

 

[Wleblanc66]

Looks like at about 5:30 he shows where to screw in the pressure switch.

 

[ssn696]

Bill,
Thanks so much for remembering this video. This is EXACTLY what I needed! The kit I am trying to reuse has a vacuum switch that opens and breaks the lockup circuit when the throttle opens and drops vacuum. It only needs a normally-open switch added to the brake pedal next to the brake light switch - push the pedal and it also unlocks the TC when you apply the brakes.
Once again, I can count on the G-body Forum's 'hive mind'.

 

[ssn696]

With the snow blowing around outside, time for some Internet engineering. Here is a list of parts needed to build your own lockup kit.
The torque converter solenoid (same part number for 700-R4 and 200-4R). This part is only needed if yours is faulty, or you got a parts/core transmission without one. The rest of the following parts mount externally to the transmission.

There is a dual-circuit brake light switch (that also unlocks the torque converter). Take out your single-circuit brake light switch and reuse the nut and lockwasher.

If you have cruise control, you may need a separate switch - check the bracket on your brake pedal; when I did this 20 years ago on a 1983 Malibu, there was a second hole for the second switch in the bracket.

There is a pigtail from Standard Motor parts that is currently out of stock at Rockauto, but may be purchased at GM or elsewhere for more money.

And a vacuum switch (not cheap) from ACDelco or Standard Motor Parts.

PT293 connector that goes on the vacuum switch.

Finally, a four-pin Weatherpack connector to plug into the transmission. This could be cut off from a boneyard donor - same connector for 200-4R and 700-R4.

 

[ssn696]

Here's a crappy sketch of how I'd wire the lockup system. Not shown is the internal wiring for the replacement TC solenoid inside the transmission. With luck, the one in your 200-4R still works, so all the connections are external to the transmission. I think this setup would work equally well on a 700-R4. When you add up the price of all the pieces, it becomes clear why Painless Wiring charges almost $200 for either the 200-4R or 700-R4 lockup kits. I saw a post a few weeks ago, 'What is this', and the guy probably pitched the $50 vacuum switch in the trash. Oops. Many of the parts on this setup may be found in the boneyard on a 1982-1985 Chevy pickup that had the 700-R4 without the computer / fuel injection. Plus, you'll get all the connectors and wiring. If your G came with a 200-C lock-up three-speed transmission with the early CCC carb / computer, you may have some of these parts already on the car. Cheers!

 

[Longroof79]

Quinn,
Thanks so much for researching and posting this very useful information. This should also be made a sticky.

 

[V8 Rumble]

Nice write up Quinn! Very helpful for all looking to do a over drive transmission

I've read these type of lock up kits turn on at about 42 to 47mph. I's this the case with this set up?

 

[ssn696]

I don't recall having trouble with early lockup. If I was looking for power, I downshifted into 3rd. Without the 4th pressure switch closure, the TC never locks up. The cheap alternative, is to put an override switch on the dash and keep the circuit open. 20 years ago, I used an old-school highbeam dimmer switch on the floor (harness and switch pulled from a '70s Chevy truck) below the parking brake pedal.

Another alternative is to ad a speed-regulated switch, for more money. Either of the following kits add another switch that does not close until a certain speed is reached that you can set. Both are about $190.

B&M Converter Lockup Controls 70248 - electronic speedometer
B&M Converter Lockup Controls 70244 - mechanical speedometer

The instructions on the Summit website from B&M for each kit are very good.

 

[pontiacgp]

For the solenoid they say you need a two wire solenoid. If you solenoid is a one wire remove the solenoid and you will see the second wire grounding with a bolt securing the solenoid. You just need to extend that ground wire and you have a solenoid you can use. When I did my 200 4R I dropped the pan, saw a one wire and had to track down a two wire. I only realized my waste of time when I removed the "one" wire solenoid.

Quinn, I still have the TCI set up someplace that I used on my 200 4R. I'll take a look for it if you want it. The postage should be cheap so it'll be on me

 

[ssn696]

Wow! Thanks! The snow is blowing hard here, so I won't be under the wagon anytime soon....