HKS Transfer Case Cooler for the GR Corolla 2023+

It protects the transfer by controlling the transfer oil temperature during continuous high-load driving.

■Product overview

• Since the transfer oil temperature in the GR Corolla's transfer case is prone to rising during continuous high-load driving on a circuit, etc., a protective control (transfer case protective control) is adopted that switches the vehicle to 2WD to prevent the transfer oil temperature from becoming abnormally high.
• The HKS TRANSFER OIL COOLER was developed with a focus on the fact that transfer oil temperature easily rises, with the aim of extending the life of transfer oil and protecting the transfer.
• For vehicles equipped with a transfer protection control cancellation program, it is possible to activate the cancellation program (cancel the 2WD mode), so the vehicle will not switch to 2WD even when driving continuously on a circuit. (If the cancellation program is activated, the vehicle manufacturer's warranty will not apply. For details, please check the warranty regulations for your vehicle.)

Vehicles equipped with Transfer Protection Control Cancellation Program

• Domestic model: March 2025 onwards
• North American version: September 2024 onwards

For details, please contact the store where you purchased the vehicle.

■ Components

■ Features

• A dedicated pipe-type cooler is used to ensure reliable cooling of the transfer oil without affecting the engine coolant, engine oil, or I/C cooling performance. The bracket that secures the cooler is designed to minimize the frontal projection area so as not to impede the flow of cooling air. (Minimizing the impact of cooling air on the radiator and intercooler)
• The oil pump is manufactured in-house by HKS and is an electric type that is capable of handling high loads and has a high flow rate.
• A dedicated pump controller is set up. Even if the pump is operated when the oil temperature is low (high viscosity), the overcurrent protection control will put the pump into standby mode, but it will automatically start operating when the oil temperature becomes appropriate.
  (Note: To avoid overloading the pump as much as possible, it is recommended to operate the pump when the oil temperature is 60°C or higher.)
  In addition, in vehicles equipped with a transfer protection control cancellation program, the transfer protection control cancellation signal (pressing the TRACK button within 1 minute after starting the engine) is automatically detected and the pump will operate. The operating status of the pump can be checked on the display of the dedicated controller. Wiring from the power supply to the electric pump is also included.
• A specially designed banjo type attachment is used for the transfer oil outlet. It is designed to be resistant to damage even in the unlikely event of an impact from the bottom of the vehicle. The banjo bolt has a PT1/8 plug hole, so oil can be changed without removing the banjo bolt. It can also be used as a temperature sensor mounting hole.

■Pump controller function

• The pump controller has the following operating modes and functions:
• Operation mode
  AUTO mode (for vehicles not equipped with transfer protection control cancellation program)
  FULL AUTO mode (for vehicles equipped with transfer protection control cancellation program)
  MANUAL mode (for maintenance)
• Current value monitoring function
  (When the pump current is above the rated value, it goes into standby mode. During standby, it operates the pump for 3 seconds every 30 seconds to monitor the current value)
• Overcurrent protection function
• Transfer protection control cancellation function (only valid for vehicles equipped with the transfer protection control cancellation program)
  The transfer protection control cancellation function can be used by connecting the vehicle's "4WD mode select switch" connector to the pump controller.

■Precautions for use

• This product is intended for use in circuit driving where the transfer oil temperature can become very high. When driving normally, where the transfer oil is not subjected to high load, please turn the pump off.
• Do not operate the engine on a circuit or other similar equipment when the transfer oil temperature is low, as this will overload the pump and piping. (As a guideline, operate the engine at temperatures above 60°C.)
• If the pump starts and stops repeatedly due to the current monitoring function while operating in AUTO mode or FULL AUTO mode, the transfer oil temperature is low. Do not use the pump in a state where it starts and stops repeatedly for long periods of time.
• Please use genuine transfer oil or our gear oil (G900 75W-90).
  Do not use high viscosity oil over 75W-90 as it will overload the pump and piping.
• The transfer protection control cancellation function is only effective for vehicles equipped with the transfer protection control cancellation program. If you use it on a vehicle that does not have the program, do not connect the connector of the vehicle's "4WD mode select switch." (You will not be able to switch to 4WD mode.)
• Installation of this product requires modification to certain areas of the vehicle (bumper air duct, undercover duct, bumper reinforcement, reinforcement, intercooler air guide).

Point!

■Fuji Speedway racing course test data

• Without the transfer oil cooler installed, the oil temperature was still rising, but the test was terminated when the oil temperature rose to approximately 150°C.
• With the transfer oil cooler installed, the test was terminated as the oil temperature stabilized at around 125°C.
• Based on these results, if we estimate the temperature at which the oil temperature will saturate if the race continues, the difference in temperature with and without a transfer oil cooler is expected to reach approximately 80°C. With the transfer oil cooler installed, the car can run at a stable temperature of around 130°C even during continuous driving.

*The above is based on in-house testing.