Automatic Gearbox Easy Change Filter Kit with Ravenol ATF for Discovery 3 and Discovery 4

The ZF 6HP26 6-speed automatic gearbox fitted to the Land Rover Discovery 3 and early Discovery 4 models was originally described as “sealed for life”. In real-world use however, transmission fluid gradually degrades due to heat cycles and mileage.

ZF 6HP26 automatic gearbox

The ZF 6HP26 is a 6-speed automatic transmission fitted to several Land Rover models including Discovery 3, Discovery 4, Range Rover Sport and Range Rover L322. Although often described as sealed for life, the gearbox relies on clean automatic transmission fluid to maintain hydraulic pressure, lubrication and cooling.

Over time the fluid and filter become contaminated with wear particles and clutch material. Regular servicing with the correct specification ATF and a replacement filter helps maintain smooth gear changes and can significantly extend gearbox life.

This gearbox service kit includes a metal easy-change sump conversion together with premium Ravenol ATF 6HP transmission fluid. The kit allows the gearbox filter and fluid to be replaced without the complex process normally required when removing the original plastic sump.

The factory transmission sump incorporates the filter, meaning replacement normally requires lifting the engine and removing surrounding components. This easy-change conversion replaces the plastic sump with a durable metal pan and a separate replaceable filter, making future gearbox servicing significantly easier.

About Ravenol ATF 6HP Fluid

Ravenol ATF 6HP is a premium automatic transmission fluid developed specifically for ZF 6HP series gearboxes including the 6HP26. Produced using high-quality hydrocracked base oils with advanced additives, it provides excellent wear protection, stable friction characteristics and high thermal stability.

The fluid offers very good lubrication at both high and low temperatures, excellent oxidation stability and reliable protection against corrosion and foam formation. It meets the specifications required for many ZF 6-speed automatic transmissions used by Land Rover.

Common symptoms of degraded gearbox fluid

• Torque converter shudder during light acceleration
• Harsh or delayed gear changes
• Gear slipping or hesitation
• Noisy transmission operation
• Poor shift quality when hot or cold

If your vehicle is experiencing any of these symptoms, servicing the gearbox fluid and filter can often restore smoother transmission operation.

Kit contents

• Easy-change metal transmission sump pan
• Separate replaceable gearbox filter
• Gearbox sump gasket
• Complete set of replacement sump bolts
• 7 litres Ravenol ATF 6HP automatic transmission fluid

The fluid supplied allows a double drain and refill process, helping replace a greater percentage of the old transmission fluid.

Easy-change sump conversion process

1. Drain the transmission fluid and remove the sump bolts.
2. Carefully cut the plastic filter neck on the original sump.
3. Remove the original plastic sump pan.
4. Install the new separate filter.
5. Fit the metal sump pan using the supplied gasket and bolts.
6. Refill the transmission following the correct ZF gearbox filling procedure.

Vehicle compatibility

Discovery 3 (L319)
2004–2009 – models fitted with the ZF 6HP26 6-speed automatic gearbox

Discovery 4 (L319)
2009–2012 – early models fitted with the ZF 6HP26 6-speed automatic gearbox

This kit is not suitable for vehicles fitted with the later 8-speed automatic transmissions.