[4ePikanini]

Right

This is the schematic I used

NB : The resistor is a 10W3Ω9J ceramic resistor.

This is the flow when the switch is OFF


This is the flow when the switch is ON


My switch - Don't mind the dust - My driveway is 4km gravel so my car tends to be dusty most of the time.

The location of where I spliced in to the wire. It is a yellow wire with thin red line



This is the workshop manual diagram of the solenoid control wiring.


Additional discussion here
https://www.4x4community.co.za/forum/sh ... ?p=1176824

[4ePajero]

Is it permanently in the "On" position?
I just hope it does not put extra stress on the flex plate. (You can buy a lot of diesel for the cost of such a failure!)

[4ePikanini]

No. It's not permanently on. If the switch is OFF the autobox behaves stock standard. If the switch is on the torque converter locks up.

My intended use for it will be highway use and engine braking on downslopes (driving mountain passes and/or off road)

I don't think the flexplate is the issue as that handles the torque of the engine anyway, albeit at slightly higher rpm if the torque converter isn't locked. The main concern is the strength of the wet plate lock up clutch, but seeing as some report towing 2 tons in 5th gear up hills with the clutch locked I'm fairly confident this mod is safe for my intended use.

Schematic of the lock up clutch

[macjohnw]

What will be the main advantages for wanting to lock up the converter?

[4ePikanini]

What will be the main advantages for wanting to lock up the converter?

it eliminates the torque converter slippage resulting in

lower revs while cruising
better economy
less "hunting"
lower autobox fluid
increased engine braking on downhills

[andrew.ashton]

Hi Marius,

I saw a lock-up switch as a product on one of the aussie sites a couple of days ago http://www.automatictransmission.com.au/news.asp. They mentioned that in the locked position the car will stall if you leave the lock on and try to stop.

Does your solution also exhibit this same characteristic?

They also have a re-ported valve body for NM series auto boxes.

While +1 for eliminating slip, one of the great things about an unmodded auto is it is near impossible to stall.

While you are poking around, how about something to keep cruise control engaged below 40kph?

[4ePikanini]

my solution is a carbon copy of their solution.

their valve body upgrade is aimed at the gen4 as the gen4 valve body doesn't allow the lock up kit to lock the TC in 1st or reverse.

the cruise is an inherent part of the ecu so shy of reflashing the ecu there is no way to mod it to work below the low speed

[andrew.ashton]

the cruise is an inherent part of the ecu so shy of reflashing the ecu there is no way to mod it to work below the low speed

Thanks Marius - is there anyone around who has is competent at re-coding / re-flashing the ecu?

[4ePikanini]

Thanks Marius - is there anyone around who has is competent at re-coding / re-flashing the ecu?

I highly doubt it.

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[4ePikanini]

I have been feeling uneasy about that resistor generating a fair amount of heat when the ecu allows 12volt through it. Essentially the ecu acts as ground so if it normally would lock up 12volt will pass through the resistor.

To combat that i have added another relay that will bypass my wiring and render the gearbox in stock form when the ecu wants to use lockup. So essentially when my switch is on and the ecu wants lockup it locks through it's own process but as soon as it unlocks my relays kick in and keeps it locked up.

With the switch off the gearbox wiring is essentially stock.

So the resisitor essentially will never see 12volt but for the split second in relays switching power around. In this method i dont know if the relay is crucial but im leaving it there to avoid the ecu maybe throwing a code.

Taking another test drive today i can clearly see how the slippage in the box wastes fuel. This mod will definitely save me on fuel economy. I will almost put a wager on it.

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