Alright I did a search about switching carbs and it said that I would need to lock the torque converter clutch. I'm not really sure what this means, I've never done it on my car. What happens if I don't do it and what difference does it make if I do?

 

Normally torque converters will slip (engine side spinning slightly faster than trans side) even at a steady cruise.

However, late-model converters have a clutch that locks the input and output together, eliminating the slip and increasing fuel efficiency and reducing the temperature of the trans fluid. I believe the clutch is electrically operated.

I don't see the need to get involved with the torque converter clutch when you change carbs.

If you never lock the converter up your cruise RPM will be slightly higher than before and your gas mileage could drop a bit, also you will be heating your trans fluid up more - that could be a serious issue depending on the circumstances.

If you never unlocked the clutch the engine would lurch to a stop when you stopped at a red light, it would be like leaving a manual gearbox in gear and not releasing the clutch when you stopped the car.

 

So if I was to get a different transmission like a th 350, or maybe a stall for the 700r4 I wouldnt have to do any of this?

 

I would imagine that you can simply disconnect the electric lock-up clutch on your existing torque converter if you want to disable the lock-up.

Just keep in mind that the converter is slipping continuously if the clutch is disabled and you risk heating the trans fluid up considerably, depending on the combination and where/how you're driving. The factory transmission cooler isn't large enough to cool a constantly slipping or loose converter.

You can watch the trans temp with a guage.

Who knows, you may like the way the car drives without the lock-up.

I think B&M used to make an under-dash switch that would let you mess with the converter clutch.

 

Most TH-350 don't have lock up converters. There are some that do, they are called TH-350C.

I assume you have a 700R4 now. You can lock up the converter manually by just running a switch into the car.

But if you're switching to a non CC carb, this is the least of your worries. I assume you know that from the other posts you've read.

 

It is not. It is hydraulically operated. The SOLENOID which opens the hydraulic path is electrically controlled.

Just picking nits...

Also, most transmissions can NOT lock in first gear. The hydraulic path isn't there. So the "lurch to a stop and stall" can't really happen. You might get some lurching if your trans can lock in 2nd... but also keep in mind, factory installed, the TC solenoid is unlocked when the brake pedal is depressed.

I can flip the "lock" switch on my TH250C and it has ZERO affect on the transmission until it shifts into 3rd gear.

 

well I was doing some reading and I found that the S10 torque converters work with the 700R4, I was wondering if anyone knows what year S10s have the "L35" converter.

Thanks

 

ask for a 1998 S-10 with a 4.3L engine code "W" if asked. 2 wheel drive.

hope this helps.

 

I had the same problem. After I installed my Holley, my TC didn't lock up. I wired a switch to my dash so I can manually control it. It works great. I think there is are instructions on how to do it somewhere in the technical articles.


1985 Camaro Z28 305, LG69, Holley 4160 w/ man choke, man TC lockup, gutted cat, K&N Filter, no egr, no smog, coconut air freshener.

 

I`ve been looking into removing the CC carb and distributor on my `83 TA. It has the 700r. Does it also have a locking convertor? This is one of the wiring problems I noticed when researching the whole computer removal process, what to do if I have a locking converter.

 

Yes you do have a locking converter. You'll need a pressure switch installed in the tranny and you'll need to run ign 12v to one wire on the harness (usually purple).

 

OK, thank you!

 

The only thing you should have to do is put the tan wire to ground. It works for me. Just put a regular rocker switch in series to manually control it.