D-Max & BT-50 Trans Cooler - 4JJ3 - 2021-On - TCB646DPK

• Isuzu D-MAX, 4JJ3-TCX 3.0L 4-cylinder: 2020 to 2026
• Isuzu MU-X, 4JJ3-TCX 3.0L 4-cylinder: 2021 to 2026
• Mazda BT-50, 4JJ3-TCX 3.0L 4-cylinder: 2020 to 2026

Automatic transmission only.

Fitment per Direction Plus as of October 2026. Check the fitment guide or send us your VIN if unsure.

The cooler sits in line with the factory transmission cooler lines, ahead of the radiator. Hot ATF runs through a fin and plate core with internal turbulators and sheds heat before it goes back to the gearbox.

• Davies Craig 32mm, 14-row fin and plate cooler, black powder coat that resists oxidisation.
• ATF temperatures down by as much as 33°C (Direction Plus figure).
• Up to 50% more efficient (heat transfer rate, BTU/hr) than a tube and fin cooler.
• 100% pressure tested at 150psi for quality assurance.
• M16 inlet and outlet fittings, pre-drilled mounting plates.

Why heat matters: Direction Plus cites ATF performance as seriously compromised above 93°C, and says a reduction of just 11°C can double the life expectancy of the transmission, ATF and internal components.

• 1x Davies Craig black 32mm 14-row oil cooler
• Vehicle-specific laser-cut 4mm 5005-H34 aluminium mounting brackets
• ATF hose (meets or exceeds SAE J1019)
• All mounting hardware

Not included: ATF. Allow for a small top-up to cover the cooler and hose volume.

• Mounts in front of the radiator for airflow and plumbs in line with the factory transmission cooler lines. Vehicle-specific brackets, no cutting or welding.
• Automatic transmissions only. Manual gearboxes do not use an ATF cooler.
• You are opening transmission fluid lines. A competent DIYer should allow 2 to 3 hours. If that is not your thing, get a workshop to fit it.
• Top up the ATF after fitting and check the level using the manufacturer's procedure. Check every fitting for leaks and route hoses clear of kinks and hot parts.
• Generally works with bull bars and winches. Make sure the cooler still gets clean airflow.
• Service: check for leaks and rock damage at each service, and rinse mud out of the fins after a dirty trip.

• Free express shipping Australia-wide, tracking number sent as soon as it is on its way.
• Afterpay, Humm, Klarna and Zip available at checkout, plus all major cards and PayPal.
• Returns, change of mind and warranty claims are handled under our refund policy.

Does it fit the MU-X as well?
Yes. Direction Plus lists the MU-X 4JJ3-TCX from 2021 to 2026, and the D-MAX and BT-50 4JJ3-TCX from 2020 to 2026.

Will it fit with my bull bar?
Generally yes. Most bars and winches do not interfere, but check the cooler still gets clean airflow and the hoses are not kinked.

Do I really need a trans cooler?
If you tow, tour loaded, drive sand or work the vehicle in hot conditions, yes. Heat is what kills automatics. Even with lighter use, cooler ATF lasts longer.

How much cooler will it run?
Direction Plus quotes ATF temperatures down by as much as 33°C. Real results depend on load, ambient temperature and how the vehicle is driven.

Does it suit a manual?
No. This kit is for automatic transmissions. Manual gearboxes do not run an ATF cooler.

How do I confirm it fits my vehicle?
Check the Direction Plus fitment guide linked above, or send us your VIN before ordering and we will confirm.