Torque Converter lock-up

**Keithy P38** · 9th March 2014, 05:46 AM

Hey guys,

A bit of food for thought here. I've been reading up on the ECU's in our Rangie's, more specifically the ones relevant to my Thor P38, and took interest in pin 32 on the Tramsmission ECU - Solenoid 3 that controls the torque converter lock-up.

There are a few questions I have and some basic stuff I already know (or at least I think I know).

Firstly, my understanding is that the converter locks up in third and fourth gear only. True or false?

Looking at pin 32, would it be possible to tap into that line, run a wire to a switch, and essentially have the ability to manually lock the converter?

Would I be correct to say that in doing so, when the newly installed manual lock-up switch is off, the converter lockup would then be taken care of by the ECU?

I'm not the brightest spark when it comes to understanding auto-electrics and the effects of tapping into things, so please forgive my ignorance!

Cheers
Keithy

**justinc** · 9th March 2014, 06:31 AM

this is how these aftermarket kits work, Wholesale Automatic Transmissions

i can't see why it wouldn't on a p38a

jc

**PhilipA** · 9th March 2014, 09:50 AM

To do this IMHO you would need to know whether pin 32 is an earth connection or supplies voltage and what voltage 5 or 12.
If an earth a simple switch to earth or AB relay would be the go.
if a voltage you would have to have a relay supplied with 12v switched by the switch . if 5 v then it becomes more complex.
Regards Philip A

**Keithy P38** · 9th March 2014, 03:49 PM

So the Wholesale kit comes with a relay and loom - those vehicles must use a +ve switched lockup unit.

Would RAVE have detail on the current type from the ECU I wonder? It would be a benefit in low range on downhill runs.

With that in mind, does the ECU lock up the converter in low range on our P38's? If it does, then it's really a waste of time setting up a manual control.

Cheers
Keithy

**Pete38** · 9th March 2014, 07:34 PM

Originally Posted by Keithy P38

So the Wholesale kit comes with a relay and loom - those vehicles must use a +ve switched lockup unit.

Would RAVE have detail on the current type from the ECU I wonder? It would be a benefit in low range on downhill runs.

With that in mind, does the ECU lock up the converter in low range on our P38's? If it does, then it's really a waste of time setting up a manual control.

Cheers
Keithy

It sure feels like it locks Keith. Obviously not when you stop but I think it locks in at low speeds in low range. Well the engine breaking is pretty good and the tacho seems to be related to increase in speed if that makes sense (so minimal slip if any)

**Keithy P38** · 9th March 2014, 08:02 PM

I tend to agree with you Pete.

Perhaps my idea is null and void - truly a testament to the superior engineering excellence that went into our P38's.

**Pete38** · 9th March 2014, 08:14 PM

Well I do hope its not true and it can be improved even more though so hoping to be wrong... But the auto in the P38 works surprisingly well off road when it's in low range mode.

**Hoges** · 9th March 2014, 09:16 PM

RAVE has a detailed explanation of the workings of the ZF auto boxes and indicates that the lock up clutch operation is governed by pre-set mapping as are gear changes etc. worth a read!

**tornado_735** · 10th March 2014, 08:51 AM

Originally Posted by Hoges

RAVE has a detailed explanation of the workings of the ZF auto boxes and indicates that the lock up clutch operation is governed by pre-set mapping as are gear changes etc. worth a read!

Somewhat off topic, but this would explain why my transmission is shifting the way it is.

My transfer box ECU fried the other night with the box in low range...pulled the ECU and jumped the selector motor with 12v to get the box back into high. The transmission now shifts as though it's still in Low range. It short-shifts, and I have no TCC lockup.

**benji** · 10th March 2014, 08:57 AM

I think it would help in low range. In low first on the overrun the fuel turns off at 1500 rpm, and then it locks the clutch quite violently (sometimes breaking traction) at 2800rpm. If you could lockup the clutch at 1000rpm I'd be so much more controllable.

It's probably in the rave section but I'm not sure what it does is the manual mode.

I'd also be helpfull towing up long hill, as you could certainly load the motor up more than it allows now.

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