700R4 question

[RamblinGMC]

When running a 700R4 with a converter lock out switch on the dash, when would that switch need to be on? Thanks!

 

[Turbo4whl]

Depending on how it is wired, you would only want the converter locked cruising in third or fourth gear. With the converter locked, you loose the torque multiplying function the torque converter is designed for.

Best is to have the converter working with the original parts or a stand alone aftermarket kit that matches or improves the factory system.

 

[RamblinGMC]

Depending on how it is wired, you would only want the converter locked cruising in third or fourth gear. With the converter locked, you loose the torque multiplying function the torque converter is designed for.

Best is to have the converter working with the original parts or a stand alone aftermarket kit that matches or improves the factory system.

Can you elaborate on the second paragraph?

 

[Ricko1966]

When running a 700R4 with a converter lock out switch on the dash, when would that switch need to be on? Thanks!

700r4 wiring has been covered at least a thousand times,use the search function.

 

[Turbo4whl]

Can you elaborate on the second paragraph?

Like Rick stated, this has been discussed for a gas engine. Bottom right shows the converter lockup switch, triggered by vacuum, and two other defeat switches complete the circuit.

You must be registered for see images attach

You still have the 6.2 oil burner? Diesel engines don't produce vacuum like a gas engine. See below there is no converter lock up switch in the vacuum plumbing.

You must be registered for see images attach

The converter lockup is controlled by the ECM, (engine control module) I do not have details on this engine.

Derek, can you help? @Blue Ox

Rick, do you still have your 6.2? @Ricko1966

 

[RecklessWOT]

700r4 wiring has been covered at least a thousand times,use the search function.

Hey this is literally the only forum I use where people don't immediately default to that response. A) this site has a garbage search function, and B) if you don't want to answer you don't have to. If someone asks a really dumb question and nobody responds, maybe the person will search harder. I like this forum because it's full of friendly people who are always willing to offer advice (within reason), let's not bring that attitude that runs rampant on other forums over here.

Also, FWIW, this guy wasn't even really asking a wiring question, he was just asking what the appropriate time to use the switch was. Honestly if I got a truck that had a converter lock switch I wouldn't be entirely sure when to use it myself, I would guess just while cruising in OD on the highway but maybe he wanted a more specific answer. Instead of just saying "use the search engine" you can either give the guy a quick answer which should take no effort if it's such common knowledge to you, or just carry on and roll your eyes at your screen. But let's not start getting all UTFSE around here...

 

[Blue Ox]

Like Rick stated, this has been discussed for a gas engine. Bottom right shows the converter lockup switch, triggered by vacuum, and two other defeat switches complete the circuit.

You still have the 6.2 oil burner? Diesel engines don't produce vacuum like a gas engine. See below there is no converter lock up switch in the vacuum plumbing.

The converter lockup is controlled by the ECM, (engine control module) I do not have details on this engine.

Derek, can you help? @Blue Ox

Rick, do you still have your 6.2? @Ricko1966

Not having any resources in front of me right now I can't help much except to offer that the diesels all ran vacuum pumps to operate some of the vacuum accessories like climate control and the modulator on my THM400. So don't count vacuum out on a diesel. It wasn't enough to operate a brake booster, but it could certainly handle the other stuff. It was a long time ago, but I converted my suburban from gas to diesel and I recall some vacuum switches on the throttle. However, I'm not sure if the factory did it the same way I did.

BTW, the mighty TDI uses a vacuum booster run by a vacuum pump on the engine. Obviously a much smaller booster than a truck, but it's not impossible.

 

[Ricko1966]

Like Rick stated, this has been discussed for a gas engine. Bottom right shows the converter lockup switch, triggered by vacuum, and two other defeat switches complete the circuit.

You must be registered for see images attach

You still have the 6.2 oil burner? Diesel engines don't produce vacuum like a gas engine. See below there is no converter lock up switch in the vacuum plumbing.

You must be registered for see images attach

The converter lockup is controlled by the ECM, (engine control module) I do not have details on this engine.

Derek, can you help? @Blue Ox

Rick, do you still have your 6.2? @Ricko1966

Yes sir I do still have a 6.2 but mine is 4l80e. If his is a factory set up he should be able to fix his as factory. If it's an add on he can use 4th gear pressure switch just like all the times we wrote it up for gas. If someone added it and just wired a toggle he can manually switch it in 3rd or 4th. I wouldn't trust myself to remember to switch it so I'd use 4 th gear pressure switch. I typed 700r4 converter wiring into the search box got 75 hits.

 

[Ricko1966]

@RecklessWOT if I came off rude,I'm sorry. I'm just tired of writing up how to wire converter lockup. Thought it would be best if he found a write up instead of just not answering. Maybe he didn't knowbits already been covered many times.

 

[Turbo4whl]

Okay, I found the answer. The gas engine uses the throttle vacuum. So the converter locks at about 13 inches of vacuum and holds it on down to about 9 inches of vacuum. This is why a vacuum pump on a diesel will not work to give a varying signal.

On the diesel, in place of the vacuum switch there is a TPS. (throttle position sensor) This switch, the brake defeat switch and the 4th gear internal pressure switch are all on to send the current to the solenoid.

 

[Ricko1966]

Can you run a 700r4 WITHOUT electrical connection?

Technically, the trans won’t care. It’s worth a little in both fuel economy and cruise rpm to get it working. Go to your nearest transmission shop, get a TH400 kickdown solenoid case connector and o-ring...

www.gmsquarebody.com

This will give you lots of pros,cons and advice

 

[RamblinGMC]

@RecklessWOT if I came off rude,I'm sorry. I'm just tired of writing up how to wire converter lockup. Thought it would be best if he found a write up instead of just not answering. Maybe he didn't knowbits already been covered many times.

I have no need for a wiring diagram, found plenty. I just simply wanted to know when to use the switch. This is not in my truck, but in another one I own. And it is gas, a 327. There is always a smart ass in every group. A simple answer or a pass would have worked.

 

[Ricko1966]

Well sir I will not call you names,I am smart though.
@RamblinGMC no way to tell when to use the switch with the info provided. Now we know it's gas. We don't what kind of vehicle it's in,we don't know if it's factory wired and someone has put a power interrupt switch to keep lock up from working or if someone has wired a toggle as a power source to lock converter anytime the switch is thrown. I'd want mine locked in 4th gear always. If the switch interrupts power in the factory setup or to a 4th gear pressure switch I'd leave it on always except when towing and only towing on 3rd gear.if it's a toggle that just switches the solenoid you need to remember to turn it off at speeds below third or forth gear.

 

[RamblinGMC]

Well sir I will not call you names,I am smart though.
@RamblinGMC no way to tell when to use the switch with the info provided. Now we know it's gas. We don't what kind of vehicle it's in,we don't know if it's factory wired and someone has put a power interrupt switch to keep lock up from working or if someone has wired a toggle as a power source to lock converter anytime the switch is thrown. I'd want mine locked in 4th gear always. If the switch interrupts power in the factory setup or to a 4th gear pressure switch I'd leave it on always except when towing and only towing on 3rd gear.if it's a toggle that just switches the solenoid you need to remember to turn it off at speeds below third or forth gear.

Thank you! Exactly the answer I was looking for. And I guess I should have added more info.It is wired to lock up the converter when the switch is thrown. Truck is a 1971, so not a factory setup.

 

[Ricko1966]

Thank you! Exactly the answer I was looking for. And I guess I should have added more info.It is wired to lock up the converter when the switch is thrown. Truck is a 1971, so not a factory setup.

Personally I'd wire it through a 4th gear pressure switch then you have to do nothing,the 4th gear switch locks it in 4th gear automatically.