Lockup Converter RE4

[locky]

Hi All
I know this has been done before and Chaz has done an amazing job with his information at https://www.chaz.yellowfoot.org/Lock...s%20Switch.htm
I have made a lockup based on Chaz's diagram but cannot seem to find how the dash on\off switch wired. Chaz's diagram doesn't seem to have it, am I missing something?

chaz-lockup.JPG

[jff45]

There is no dash on/off switch needed because that design is based on the system cutting out when the brakes are applied.
The disadvantage of that system is that it cuts out the lockup every time you touch the brakes and I found that to be a nuisance when running in traffic on the highway.

The Park/Neutral cutout relay in that design was my contribution to Chaz’s original design.

I since did a complete redesign of the circuit and use a Jaycar frequency switch that “arms” the system at a chosen vehicle speed so you can activate it from that speed. It cuts out automatically when the speed drops below a lower chosen speed. This design eliminates the need for the Park/Neutral relay and the brake switch relay.
The Jaycar frequency switch was a kit that originally had to be soldered together but they now sell it ready made.

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[locky]

Thanks jff45 for all your valuable info.
I understand how the cut out works to momentary switch when activated while the brakes are on! It's an override for use with steep descent while 4wding.
And your system as described is awesome for general driving or towing as you have control above a certain speed stopping the "on" issues when stopping, and for most general driving that is the ideal solution.
As I do an amount of 4x4 stuff the downhill control appealed to me and generally when I go off road I tow a caravan for the camping part. I know this is not everyone!
Anyhow when I saw Chaz's setup he says in the guide about using his system while in 3rd Gear (Direct drive) while towing to reduce heat, then using the momentary foot switch for the use of the downhill function, I thought that's what I need.. Perhaps I mis-understood that although it's all on the same page.
On the page where I got the diagram in the link above he mentions "I normally lock the converter in 3rd gear and when driving up long hills, especially when towing" and a "Dash control switch is in an image". Also he mentions about being aware of your driving because the car could stall if you have left the the lockup on.
Have I misunderstood that this setup won't do both? If so I apologise for my ignorance but ask if its possible to have the best of both worlds?

[jff45]

You can certainly fit a switch into the 12v feed line if you want to completely isolate the lockup function.
The only risk of damage when stalling is if you somehow try to deliberately come to a stop without touching your brakes while the TC lockup is engaged.

The biggest advantage of a manual TC lockup is being able to control the lock/unlock behaviour of the trans which generates unnecessary heat. It's also useful for bringing trans temps down when towing.
Be aware that it can be misused as well. Applying too much load to the lockup clutch can result in slippage which will damage it over time. This is why the factory control releases the lockup very quickly when it gets even a slight load signal from the TPS.

I believe the GU version of the RE4 can lock the TC in low 1st anyway for steep descents. You also have the option of using reverse if the descent isn't too long.

[locky]

Thanks again John
I have 2 cars and wanted this in both but after seeing your system using a speed trigger I will do that in the tourer.
With the GU I am originally talking about I understand the nuances of leaving the switch on when stopping etc. But it's just a fun bush car that is only driven on 4wd trips and would just have to be more diligent in remembering when to have it on of off.
Sorry to be a pain but I have 2 questions:
If I put a switch in the 12v feed line somewhere just after the fuse; what wouldn't the result be? I ask this because in Chaz's diagram its connected to ignition, wouldn't it be on all the time, and just work as normal using the TCM for Clutch Lockup. then lock if overridden using the momentary switch.
Therefore where would the switch go?
The 2nd question I have I did a bit of a search for the Jaycar frequency switch but couldn't find. Can I get a little more info that as I have another car that is a tourer and that system would be perfect?
Cheers

[jff45]

The only advantage of adding a switch into the 12v feed line is that it allows you to cut power to the momentary foot switch. I found the foot switch to be a bit of a nuisance because I often trod on it inadvertently and it engaged the lockup when I didn't need it. You can also cause unnecessary wear if you engage the lockup harshly while accelerating. The factory lockup is done via PWM so it engages gently to avoid the shock.
If you switch off the manual TC lockup circuit, the TCU will still control the lockup through the 87a -> 30 pins on the Control relay.


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