Idemitsu ATF Type HK Automatic Transmission Fluid 5-Quart — SP-III Spec, Smoother Shifting & Thermal Stability

Idemitsu ATF Type HK is a 5-quart automatic transmission fluid formulated to meet Hyundai/Kia SP-III requirements and deliver smoother shifting, improved seal compatibility, and thermal stability for modern automatic transmissions.

This 5-quart container of Idemitsu ATF Type HK (part number 30040097-95300C020) is designed specifically for transmissions that require the SP-III specification used by many Hyundai and Kia vehicles. The formula focuses on oxidation resistance, seal conditioning, and minimizing sludge or varnish buildup to help transmissions operate consistently under city and highway driving.

What benefits does Idemitsu ATF Type HK provide for automatic transmissions?

Idemitsu ATF Type HK supports reliable shifting, reduces wear on clutch packs and gears, and helps preserve transmission internals by resisting breakdown at high temperatures. While it doesn’t replace scheduled service, using the correct ATF specification helps maintain performance and reduces the chance of fluid-related issues.

• Smoother shift feel for predictable gear changes
• Oxidation and thermal stability to slow fluid degradation
• Seal compatibility to limit leaks and preserve gasket life
• Formulation that reduces sludge and varnish formation

How do I know this ATF is right for my Hyundai or Kia?

Check your vehicle owner’s manual or the transmission filler cap for the SP-III (or equivalent) specification requirement. This Idemitsu ATF Type HK is produced to meet those SP-III performance targets, making it suitable for models that list that specification.

• Confirm the manual lists SP-III or the equivalent spec
• Use the correct quantity and service interval recommended by manufacturer
• When in doubt, match fluid part numbers or consult a technician

How does this fluid affect maintenance and transmission life?

While no fluid can eliminate the need for regular maintenance, an appropriate ATF helps reduce thermal and oxidative stress on transmission components. Consistent use of the correct fluid can decrease deposit formation and protect seals, which supports longer service intervals and fewer repair needs related to fluid failure.

• Reduces varnish and sludge that impair clutch operation
• Helps maintain hydraulic properties for reliable pressure control
• Supports seal elasticity to prevent leaks between services

Can I mix Idemitsu ATF Type HK with other transmission fluids?

Mixing different ATF formulations is not recommended because additives and friction characteristics vary between brands and specifications. If you must top off and the exact fluid is unavailable, use caution and replace with the correct fluid at the earliest service to avoid potential compatibility or performance issues.

• Avoid mixing unless it’s a short-term emergency measure
• Plan for a proper full fluid exchange with the correct ATF soon after
• Consult service documentation or a professional for compatibility guidance

Who is this for: Idemitsu ATF Type HK 5 quart is aimed at owners and technicians servicing Hyundai and Kia vehicles that specify SP-III automatic transmission fluid. It suits people doing scheduled fluid changes, rebuilds, or top-offs who want an SP-III-grade product with attention to oxidation resistance, seal protection, and shift quality. If you maintain your vehicle according to manufacturer guidance and want a purpose-formulated ATF for SP-III transmissions, this Idemitsu product is a practical choice.