I’ve been asked many times ‘Why did Toyota program their transmissions to slip so much and create heat which reduces the life of the transmission fluid?’
There may be many reasons why the Toyota Engineers did this but I mainly see it as to keep you going back to Toyota for assistance!
Thankfully due to some very clever people, transmission torque converter slippage can be greatly reduced by installing a Torque Converter Lock Up (TCLU) kit. The TCLU kit is designed to apply power to the torque converter lock up solenoid above a selectable speed and not rely on your vehicle or the road conditions or the driver throttle input.
Stockwell Automotive’s Stocklock
Stockwell Automotive’s Stocklock is designed for the Toyota Landcruiser, Hilux and Prado. It takes control of the torque converter lock up solenoid to greatly reduce the amount of slippage which is the main contributor of excessive gearbox temperatures. When the torque converter is unlocked then more fuel is being wasted as the transmission can’t put the engine power to the ground.
Stocklocks kits are available in three models: single speed, dual speed and triple speed. The most popular kits are the dual and three speed units as they offer better value for your dollar.
The 200 series Landcruiser has all three options available whilst the Hilux and Prado only currently have two options being the single and the dual speed kits.
Single Speed Stocklock
The single speed kit has an engage speed of 82km/hr and disengages at 78km/hr. It locks the torque converter in gears 4th, 5th, and 6th and is designed for general driving and long-distance touring. The transmission will still dropdown gears as required for optimum engine performance.
Dual Speed Stocklock
The dual speed kits have two functions: high speed which locks torque converter in gears 4th, 5th and 6th from 82km/hr and disengages at 78km/hr, and low speed which locks the torque converter solenoid from 32km/hr while disengaging at 28km/hr in gears 2nd, 3rd, 4th, 5th and 6th. This kit is designed for general driving, long distance touring and those who carry heavy loads such as caravans, boats and trailers. It has a fully automatic operation with no need to turn the unit off to come to a stop. The transmission will still dropdown gears as required for optimum performance.
Triple Speed Stocklock
The triple speed kit is essentially a dual speed kit but can also lock the torque converter solenoid in 2nd, 3rd and 4th gears (the highest gear in 4×4 low) from 10km/hr in low range 4×4. This kit is designed for general driving, long distance touring, towing heavy loads and those who do the harder tracks and/or high country who want engine braking down to 8kmhr. The transmission will still dropdown gears as required for optimum engine performance.
Stockwell Automotives Stocklock utilse Pulse Width Modulation (PWM) technology which integrates seamlessly with Toyota’s PWM technology so they work together and not seen as something foreign where fault codes are usually experienced.
Stocklocks have a soft engage/ disengage so no harsh transmission shifts occur and gear flaring from 6th to 5th is eliminated making the vehicle and transmission much more pleasant to drive.
Stockwell Automotive Stocklock kits have additional safety features built in such as the ability to be able to unplug the Stocklock from the vehicles ECU harness and revert the vehicles transmission back to standard if you think you’re having issues out in the bush or on the road or you want to upgrade to a different kit.
A reduction of fuel usage will be evident with customers reporting a saving of up to 3 litres per 100 kms but around 2 litres per hundred is more achievable.
Xpedition Concepts is the South Australian agent and the kits are available for purchase from our online store.
Thanks for reading, Angus