Torque Converter Lockup

and Gearbox Remap

LandCruiser 200

If you've watched my initial review of the 200, you'll know that I've always been less than impressed with the behaviour of the automatic transmission.

This article and video will cover a major improvement to its operation, thanks to a system to adjust the operation of the torque converter lockup function.

Update August 2019: I have also had the gearbox software remapped. The original article covers the lockup kit. The remap is documented further down the page.

Affiliate link notice: This page contains eBay affiliate links, for which I may receive a commission if you click on a link and make a purchase of any item on eBay. The price you pay is unaffected. 

The issues with the 200's Aisin transmission

Compared to almost every other modern automatic transmission, the 200's Aisin AB60F transmission behaves very poorly in a number of areas.

With the torque converter unlocked, change points -except for the change to 5th gear- are generally too high in the rev range to take advantage of the twin-turbo diesel engine's flat torque curve. This means the engine revs far higher than it needs to, generating additional wear and consuming more fuel than required.

The 'sports shift' system doesn't work like any other light vehicle I have ever driven, only allowing you to restrict changes into taller gears rather than actually holding the gear selected. For example, if you select S5 then all it does is restrict the gearbox from changing into 6th. It does not hold 5th gear preventing a downchange to 4th. Again, this means you cannot even manually take advantage of the low-down torque of the engine.

But by far the most annoying 'feature' of the transmission is the operation of the torque converter (TC) lockup. The TC lockup function fully locks the engine to the gearbox, improving fuel economy and preventing heat buildup in the transmission fluid. The 'Cruiser's TC essentially only locks in 5th and 6th gears, at high speeds and under light throttle. By contrast, most modern automatics are programmed to engage the TC lockup as soon as possible and in as many gears as possible, particularly when operating in 'sports shift' mode. This is probably best illustrated by a table comparing the operation of the 'Cruiser's lockup with that of the ZF 6-speed transmission in my GT:

Lockup options include Richards, Stocklock, ECONlock and Wholesale Automatics

D S4 S5 S6
4th No 70km/h No No
5th 95km/h* locked out 90km/h 95km/h*
6th 105km/h locked out locked out 100km/h
WordPress Table Plugin

Landcruiser 200 (Aisin AB60F) torque converter operation

D S4 S5 S6
4th 50km/h 40km/h locked out locked out
5th 70km/h locked out 50km/h locked out
6th 85km/h locked out locked out 72km/h
WordPress Table Plugin

Falcon GT (ZF 6HP26) torque converter operation

* In practise, the 'Cruiser rarely locks in 5th gear while under acceleration. It tends to remain unlocked until cruising speed is reached, eventually locking in 6th. Then, under load it unlocks and changes back to 5th, then re-locks in 5th after a few seconds.

Coming up with a solution

The best way to fix the programming of the transmission would be to modify or replace the computer which controls the gearbox. This option is available for many transmissions around the World, but in the case of the 200 it's exceedingly difficult. While most vehicles have a dedicated Transmission Control Module (TCM), the 200's transmission is controlled directly by a combined engine/transmission ECU, and (at the time of writing) nobody has managed to successfully 'uncouple' the transmission control from the ECU. This means that it's currently impossible to customise the behaviour of the transmission, so you're pretty much stuck with the existing shift points and sports-mode operation. See remap update below.

What can be changed is the operation of the torque converter lockup, by overriding signals to the unit and sending phantom signals back to the ECU to prevent a check-engine warning. At the time of writing, there are three different companies manufacturing torque converter lockup systems for the 200:

One option is the European-made ECON*lock. Still the most automated option available, it's also the most expensive at about €1390 (A$2000). The manufacturer also claims it's the safest option, because it generates a pulse to operate the lockup valves, similar to the factory system.

Next up is the Wholesale Automatics manually-operated lockup switch. At a cost of about $600, it performs a lockup of the torque converter through manual operation of a dash switch, at any speed and in any gear between 2nd and 6th. Like the ECONlock, it uses a pulse to activate the lockup valves.

Then there's the system I've chosen, produced by Stefan at Richards Auto Electrical in South Australia. It's a speed-sensitive automated version, with the driver able to preset the speeds at which the TC will lock and unlock. The kit (which suits both the 200 and Lexus LX450d/570) is available direct or on eBay (where there are also bulk discounts). They also produce a manual system similar to Wholesale's switch, for around $300). Rather than the solid-state pulse used by the ECONlock and Wholesale systems, the Richards system uses a series of Bosch relays and a resistor to activate the lockup valves.

In my opinion, having the system automated to lock at a preset speed is by far the best option for a device like this. Its operation requires no input from the driver, so there's no need to constantly think about locking and unlocking it as you drive at different speeds. You maximise the fuel economy benefits of the system. I've also added a 3-way (on-off-auto) override switch, which allows me to revert to factory operation and also force lockup at lower speeds than I've preset, should the conditions require it.

Richards also produce a torque converter lockup kit for the Prado and Hilux.

Update June 2016: Several companies are now offering remaps or reprograms of the transmission control functions of the ECU. I have made several enquiries in an attempt to get full details of what parameters can be changed, and to what degree. However little information has been forthcoming. I will continue to investigate this option.

Update: Landcruiser 200 Transmission Remap

I knew Richards had been working on remaps for the auto for some years, but I wasn't convinced they had reached the level I'd be happy with. In April 2019, I got some feedback from another owner that made me revisit the idea. I gave Stefan a call to get the details on their latest version, and I liked what I heard. Chasing feedback, Stefan offered to come and remap my transmission at no cost when he was passing through a few weeks later, and I took him up on the offer.

The highlights of the remap are:

  • Lower engagement speed for 6th gear: Now engages at around 92km/h in Drive, under light throttle.
  • Higher throttle before kicking down from 6>5 and 5>4: The map ramps, so (for example) It drops into 6th at 92km/h if you are at <20% throttle. By the time you reach 100km/h, it needs ~50% throttle before it kicks back to 5th.
  • Smoother gear changes: The remap applies torque reduction during gear changes. This makes a huge difference to gearshift quality, particularly when the lockup kit is active.
  • Multiple maps: The remap has different settings for 'Drive', Drive+PWR', 'S' and 'S+PWR'.
  • Allowing 5th and 6th gear to operate in low range: I didn't go with this option, but it's available if you want it, so you're no longer limited to 4th in low range.
  • Elimination of MIL light: The remap extends the parameters required to generate the P2757 fault code, and stops the malfunction light sequence from appearing (although it still logs any fault code internally). The fault light can be a side effect of the TC lockup kits. I got this code perhaps once or twice a year, but haven't had it at all since the remap.

The verdict:

As I write this, I've now driven around 11000km since the remapping. That's roughly 1500km around town, 8500km (towing) on the Cape York trip and 2000km (not towing) to Melbourne and back.

I am absolutely rapt with the operation of the transmission since the remap. When you're not towing, it effortlessly drops into 6th gear at highway/freeway speeds and holds it even when climbing decent inclines. Between Sydney and Melbourne at 110km/h, it only dropped back to 5th on two occasions heading North, and once heading South. Even when towing (a 1.6T camper), it now comfortably holds 6th gear up moderate inclines. The vast majority of ~100km/h highway driving on the Cape trip was spent in 6th gear. Similarly, on the dirt sections at 80-90km/h, it easily holds 5th (locked at ~1500rpm) under almost all conditions.

Cruise control is now more usable, with better holding of gears reducing the hunting that was common on undulating roads. The reluctance to change back into 6th on the flat is now gone as well.

My only complaint to Stefan was that the slightly different settings in S6 (compared to Drive) sometimes caused it to jump straight from 6th to 4th when climbing a hill, but this has apparently been addressed in a later version of the remap, and in any case doesn't happen when in Drive.

At the time of writing, Richards were only offering the remap directly (rather than via their dealers), although this is apparently under review. If you go to their workshop in SA, they will reflash via the OBD port. Otherwise, if you remove your ECU, they will arrange for a courier to pick it up, take it to them where they will reflash it, then courier it back to you. You need to have a lockup kit (any brand) installed in order to have the remap done.

Pricing as at August 2019 is:

    • Lockup kit DIY install (inc delivery): $740
    • Lockup kit supplied and installed: $945
    • Lockup+Remap (DIY lockup install, courier pickup/return of ECU for remap): $1555
    • Lockup+Remap supplied and installed: $1745
    • Remap only (in-store, or courier pickup/return of ECU): $895*
      *Must already have a lockup kit installed (any brand)

Contact Richards Auto on (08) 8532-1411 for details/current pricing.


The "Installation" section should not be taken as instructions. It is simply a documenting of the procedure I followed for my own installation. No warranty is provided as to the accuracy of the information, and/or whether it applies in your situation or to your vehicle. If you're not qualified and/or don't have the correct equipment, get the lockup kit fitted professionally.

  • There are potentially lethal dangers resulting from the use of power tools.
  • There is the potential for expensive vehicle damage from improper installation.

If you undertake your own kit installation, you do so entirely at your own risk.


Links below are eBay affiliate links. If you click on a link and make a purchase, I may be compensated by eBay. The price you pay is unaffected.

Installation Tips

Richards supply comprehensive installation instructions with the kit. I followed these instructions in the video above and found them to be accurate, so I'll only add a few tips below and also document the wiring of the ON-OFF-ON switch, which allows me to choose between On, Off or speed-sensitive automatic operation of the lockup.
Step numbers correspond to the supplied instruction steps.

Update 2020: The Richards kit, including the supplied switch, has been changed since this article and video were produced. Follow the instructions supplied with your version of the kit.

Click to Enlarge

Step 1:

  • Tape the kit wires to a piece of rigid wire, then pass it through one of the two nipples in the Toyota grommet, after cutting the end of it off. I already had some wires in these nipples from previous installations, but they still passed through reasonably easily.
  • It's not mentioned in the supplied instructions, but I advise connecting the orange battery wire via a fuse for additional safety. I just connected mine to one of the spare terminals on my accessory fusebox.

Step 5 and 7:

I have covered the dash pull-apart previously if you would like any tips.

Step 6:

See below for the changes required to enable On/Off/Auto operation. Note that this change is not required for current kits, as they now include the 3-way switching.

Adding a switch to enable ON / OFF / AUTO operation

UPDATE 2020: The Richards kit now includes a 3-position switch as standard.

While I generally wanted set-and-forget speed sensitive operation of the lockup kit, there are times when it would be handy to override the speed setting and lock the TC manually, such as long downhill runs for engine braking, or long low speed climbs to keep the ATF temperature under control. This can be achieved by installing an ON-OFF-ON switch, where one of the ON positions gives automatic control and the other gives manual override.

There are plenty of such switches available, typically with I O II markings, but I wanted an illuminated switch design that was neat and clearly showed which mode was active. I thought I'd found the perfect one, being a Cole Hersee 58312-AG, available on special order through Repco and Bursons for about $20 plus any order fee. Unfortunately, after testing it I discovered that the illumination is wired ridiculously, so that the opposite light illuminates from the depressed side of the switch. For example, if the green side is down, then the amber light is on. But because I hadn't found any suitable alternatives, I persisted with the switch, disassembling it and rewiring the lighting so that it operates logically. I then printed some labels to apply to the switch, giving the result you can see in the photo.

Note that I removed the "Idle Up" switch to install the lockup switch. It serves little purpose in a warm country like Australia.

Installing the switch into the lockup kit circuit:

  • Instead of connecting the green kit wire direct to the back of the dash power outlet (Step 6), run a new wire from the power outlet up to the POWER IN terminal of your switch.
  • Run the green kit wire to one of the POWER OUT terminals of the switch. This gives automatic operation.
  • Run another wire from the switch's 2nd POWER OUT terminal back to the lockup kit. Then splice it into the green wire that runs between the relay block and the control box of the kit. This connection overrides the speed controller, giving you manual operation.

You now have three modes:

  • ON - This will lock the TC at any speed in any gear except 1st and reverse. You'll find that the vehicle will seem a little rough and jerky at low speeds, and it will lug at low revs when you're under about 60km/h. It can be very useful for engine braking or low speed hillclimbs, but is best used in combination with S mode on the gearbox so you can select a suitable gear.
  • OFF- In the centre position, the transmission reverts to factory operation. Handy when you take it to Toyota for a service.
  • AUTO - The torque converter will lock and unlock automatically at the pre-selected speeds.

Adjusting the lock and unlock speeds

The lockup kit comes preset to lock at 78-80km/h and unlock at 74-75km/h, assuming you have standard tyres (larger tyres will affect the settings).

As I have larger tyres and I also wanted to reduce the lock speed slightly, I had to change the preset values in the controller. It's a reasonably simple process:

  • After completing the installation, remove the 4 screws retaining the top of the controller box, and slide out the controller. You'll see a display plus a series of 4 black buttons below the display (labelled U, D, S, R) and dip switches above the display. Be careful not to damage the electronics via a static discharge.
  • To find the setting you want, you need to drive at the speed you want, then push the 'R' (read) button at the bottom right of the display. The display will show a number, which you need to take note of. For safety, have an assistant push the button, instead of trying to do it while you're driving.
  • To change the LOCK speed, push up the 1st DIP switch in the bank of 8, then push the 'U' (up) or 'D' (down) buttons to change the value, followed by the 'S' (set) button.
  • To change the UNLOCK speed, push up the 1st and 3rd DIP switches in the bank of 8, then push the 'U' (up) or 'D' (down) buttons to change the value, followed by the 'S' (set) button.
  • Return the DIP switches to the down positions. Never change the position of the DIP switches in the bank of 3.
  • There must be a minimum difference of 5% between the LOCK and UNLOCK values. In my case, I chose LOCK at 49 (~77km/h) and UNLOCK at 44 (~69km/h).

It's up to you which speed to set the lock/unlock at. I initially wanted a lower speed, but found that the vehicle lugs in Drive when below about 65km/h with the lockup engaged. You can overcome this by selecting a lower gear (eg S3, S4), but that would almost defeat the purpose of automating the system, and I think the fuel economy benefits would be negligible. Note that according to Richards, if you want to set an automated speed below 35km/h, you need a different controller box.

Testing and results (Lockup kit only - pre remap)

Following installation I drove a test loop, once with the lockup engaged and then again with it disengaged (ie: standard factory operation).

The loop was 75km in length, and consisted of around 25km of undulating 80km/h rural roads, 20km of hilly 80km/h highway, 20km of 60-70km/h suburban roads and 10km of flat 90-110km/h freeway. Even though the TC lockup was only applicable for around 3/4 of the loop, it resulted in an overall 9% fuel economy improvement from 12.8l/100km in standard form, down to 11.9l/100km with the TC lock engaged. The largest difference occurred under heavy throttle at 90km/h, where the ultragauge reported almost 50% lower consumption thanks to the TC being locked. I expect that when towing my camper-trailer at highway speeds, fuel consumption will be improved by 20-30% on average.

The fuel economy improvement only tells part of the story though. The other part is drivability, and the difference is remarkable. Once the TC locks, the vehicle feels far more responsive. You can feel the torque of the big V8 powering you forward, instead of watching the tacho (and fuel consumption) leap with little acceleration to show for it.

This one modification has totally transformed the highway performance and economy of the 200. This is the way Toyota should have programmed their gearbox to operate.

Update 17/10/14 - Check engine light

Since fitting the kit several months (and about 10,000km) ago, I've twice experienced a "check engine" warning related to the TC lockup. The exact combination of warning lights displayed are: Check engine, 4-Lo (flashing) and Traction Control.

The code given by the computer is P2757, which indicates that the computer sees that the TC is locked, but thinks it shouldn't be (or visa-versa). After speaking to Stefan, it seems this is an occasional side-effect of the lockup kits where they can't fool the ECU fast enough, causing the warning under certain circumstances when the TC locks or unlocks.

There's no side effect of the warning (limp mode etc), and there's no damage being done. The only issue is the lights on the dash. If you have an Ultragauge or Scangauge II (or similar), you can reset the warning immediately. If not, switching off the vehicle for a couple of minutes usually resets the warning (although it is stored in the ECU). Otherwise, you can disconnect the batteries for about 30 seconds.

It seems to be a rare occurrance and I'm not concerned about it, but it's worth noting that this can occur for reference.

Update 2019

The check-engine light issue has been completely solved with the transmission remap, discussed above.

Use the icons below to
share or like this page:


Scroll to Top