Locked torque converter do's and don'ts?

[-Nemesis-]

Posted this at lcool but its pretty quiet there these days, so the call goes out to the Outers techies too!


After a lot of research I've finally made my own manually lockable torque converter set up in my 2001 FZJ105 (4 speed A442f)

Now, it seems much better driveability in lower speed situations when it's on. But, this is my first auto and I know little to nothing about locking/clutched torque converters, so I'm hoping those with genuine knowledge on the subject can share some tips. Issues like:

What gears shouldn't - if any - you use the locked converter in on road?

Is it okay to let it change gears when locked? I did by accident and gear changes seem normal, if only slightly crisper..

What about compression deceleration from speed with it locked, is this bad for the auto as they're not used to it? Anything from purposefull downshifts to control speed and use compression braking, to gentle deceleration between corners etc...?


Any general do's and don'ts? I can see I'm gonna get some decent fuel savings, especially around town with the turbo set up as it has more then enough torque to lug along at the lower revs without the converter sapping power.

[simkell]

The idea of a torque convertor is to multiply torque under heavy loads and once under cruising speed get to position in which it is almost a 1
:1 lock up (coupling point). The lock up clutch then makes it true 1:1 lock. The lock up clutch isn't designed to take shock loading which will happen when down and upshifting. You may get away with it for awhile but it will fail, prematurely. Also you will not get any torque multiplication whilst the lock up clutch is engaged.

The lock up clutch can operate in any gear that you like, however I think lock up in first would be a waste in time.

Hope it was helpful.

[-Nemesis-]

Thanks mate. I mainly installed it for towing and driving at speed where the ECU likes to continually en/disengage the lock up. I basically made my own version of this for $200 less, but with less hardware and more reliability:

http://www.automatictransmission.com.au ... wsId=12101" onclick="window.open(this.href);return false;

Really it'll only be for 3rd and 4th gear runs. Though, it does seem to drive alot better in 2nd with it on around town, mind you I am used to manuals. It kinda bugs me all the wasted power and energy when I turn into a street and touch the accelerator, to watch the tacho sit on 2200rpm while the speedo slowly goes from 20km/h to 50km/h with out any rev change. There can't be an advantage to all that energy loss surely, especially with the grunt of a the turbo on mine it doesn't need any torque multiplication lol

However, I don't want to damage anything so hence I ask the question first. All i've found on the net is how people reckon its the best thing they did, but no tech on what not to do. My 105 only has 80k on the clock so I want to get many times this with no issue. I didn't wire it up to race the gears etc...

[bazzle]

Ask Orto (Rodey) on here:

http://www.automatictransmission.com.au ... wsId=10672" onclick="window.open(this.href);return false;

Bazzle

[drr]

What's it like going downhill in low 1st? I was toying with the idea for my cruiser to get lower crawl speed.

[udm]

Me too here on my first auto... nemesis, do you have any info for us about the mods done and whats involved?

By the way, do you think it is possible to have it switch off by hitting the brakes, like the way cruise controls work?

[DamTriton]

Me too here on my first auto... nemesis, do you have any info for us about the mods done and whats involved?

By the way, do you think it is possible to have it switch off by hitting the brakes, like the way cruise controls work?

http://www.outerlimits4x4.com/viewtopic ... 8&t=218892" onclick="window.open(this.href);return false;

Still in testing though so be patient.

Yes you could switch with the brakes, but it would place an extra layer of complexity. Not difficult but just something else to go wrong.

Ideally if using for engine retardation you would want both the brakes usable and LUC locked anyway.

"Add lightness and simplicate"

[gingerbreadman]

a locked torque converter in any gear except top gear and at cruise speed is totally useless. the loc up is the weak link in a torque converter so abuse it long enough and it will surely fail. when chev brought out loc up torque converters way back in the 81 corvette its was controlled by a computer to come on only when a certain rpm matched a certain cruise speed which was around 2000rpm with 55mph. any change at throttle or downshift would disengage the loc up converter. sure transmissions have come a long way since that TH350C but its still only there for fuel economy when towing or at cruise speed. your converter is designed to flare and work as a automatic clutch , not to be locked .are you sure its engaging in those lower gears your mentioned cause im suprised its not falling on its face?

[MightyMouse]

In my experiece they are a light duty mechanism only - easily damaged.
Also differential speed is important - avoid locking the converter when theres more than the absolute minimum of speed difference across it.

I've built a number of transmission controllers for Aisin Warner auto's ( electrically shifted - mechanically modulated ) which gave full auto and full manual mode and the mapping exercise was pretty significant. Luckily there were a number of OE shift maps available so a lot of the hard work was already done, and the lockup conditions known - most of the effort was just to provide the full manual functions. I used a small PLC whcih really wasn't cost effective unless you had one lying around.

At the end of the day I trashed the whole lot and went to a interlocked push putton array and some simple logic and just drove it in "manual" all the time and ignored the lockup.

It was fantastic and simple... and oh so versatile - i wish more recent autos were as easily controlled.

[KiwiBacon]

I put an electric lockup over-ride into my nissan shopping trolley about 4 years ago. With the idea that if it did cause the death of the box it'd be a good excuse to go manual.

Short storey, I haven't been able to kill it at all. The lockup is of great value climbing hills and cruising. I use it in all gears at different times to save fuel and keep the auto box cool.
I have left it locked up most of the time on upshifts and downshits. On upshifts you barely notice the difference, on downshifts they can be rough.

The worst thing you can do is pull it into gear from neutral when the lockup is on. That feels really bad.
I've stalled the car plenty forgetting it is on, one thing to keep in mind is at low revs the box hydraulic pressure is low enough that the clutch packs take up shock and shifting is still quite smooth. It's getting it wrong at high rpm (i.e. manual shifting) which gets rough.

On this car the speed difference and torque multiplication is all over by about 2000rpm. So engaging it under 2000rpm can result in a lot of shifter shock, over 2000rpm it's barely noticable unless you've got your foot in.
Best thing, engage it before flooring it.

[Skegbudley]

Chaz on the Patrol forum came up with this lockup mod a while back.
Its been done now by heaps of people without any problems.
http://www.chaz.yellowfoot.org/Lockup%2 ... Switch.htm" onclick="window.open(this.href);return false;

[-Nemesis-]

Yeah the concept wasn't mine, nor hard. The hardest bit was finding out the right wires etc

I wonder what the clutch differences are between the Niss and Yota?


Also, for the LED. I'm using a nice crome bezeled LED from Jaycar ($1.75), the only catch I discovered is they're 2v, so you need a resistor in line to stop them blowing. Better than a flashing 12v LED imo...

[KiwiBacon]

Yeah the concept wasn't mine, nor hard. The hardest bit was finding out the right wires etc

I wonder what the clutch differences are between the Niss and Yota?


Also, for the LED. I'm using a nice crome bezeled LED from Jaycar ($1.75), the only catch I discovered is they're 2v, so you need a resistor in line to stop them blowing. Better than a flashing 12v LED imo...

I have two led's wired in. Green says the computer is trying to lockup the clutch, red is manual over-ride. The way I've wired it in red over-powers green though, the over-ride needs to be off before the green LED will work as an indicator.

[Frankenyota]

I looked at putting in the lock up switch as i thought the auto was overheating when towing. But after speaking with Rodney at wholesale autos, he explained that the cruiser auto has lock up in 3rd and 4th gears, and it's unlikely to be causing the overheating.
So i fitted a auto temp gauge to monitor the temps.
Turned out the auto was sweet.
Maybe you need an valve body upgrade for the auto, alot of people do this for a turboed petrol.

I am want to do a lock up switch in the lux but was warned if not used correctly it will wear out the box.
Never seem to get it to lock up in the bush, which means excessive heat.

Matt