Castrol SAF-XO Final Drive Lubricant - 1 Litre - TYK500010
The genuine Land Rover final drive lubricant for non-locking differentials carries part number TYK500010. It is a one-litre bottle of Castrol SAF-XO, a fully synthetic SAE 75W/90 multigrade gear oil that became the prime factory recommendation for Land Rover's transverse and longitudinal final drives across the modern Range Rover and Discovery range. The oil supersedes the earlier Castrol G728 specification and remains the correct fitment for the non-locking (open) front and rear differentials on the cars listed below.
TYK500010 fits the Discovery 3 (2005 to 2009), Discovery 4 (2010 to 2016), Discovery 5 (2017 onwards), Range Rover L322 (2002 to 2012), Range Rover L405 (2013 onwards), Range Rover Sport L320 (2005 to 2013), Range Rover Sport L494 (2014 onwards) and the New Defender L663 (2020 onwards). It is the correct oil for the open differential variants on these vehicles. Cars equipped with a locking rear differential or electronic limited-slip differential use a different specification, so confirming differential type before ordering is important on any Sport or HSE model.
Castrol SAF-XO carries API GL5 service classification, with full approvals to MAN 342 SL+ for back axles, Scania STO:1, Alpina, BMW and ZF TE-ML 05B and 12B. The BMW approval matters directly here: Land Rover's modern differentials use ZF-derived hardware closely related to BMW final drive units, and SAF-XO was originally developed as Castrol's prime synthetic recommendation for BMW non-LSD final drives. The same oil specification carries across to the Land Rover applications it supersedes, which is why the genuine TYK500010 service fill is Castrol SAF-XO in unbranded Land Rover livery.
The technical specification supports demanding axle conditions. SAF-XO holds a viscosity index of 162, a flash point of 220°C and a pour point of minus 51°C, giving it the cold-flow performance needed for winter starts and the thermal stability needed for sustained motorway speeds and towing. Viscosity at operating temperature (100°C) sits at 15.7 cSt, with 103.7 cSt at 40°C. Fully synthetic base oil and a heavy-duty additive package provide the load-carrying capability and foam resistance needed to protect the hypoid gear set under the kind of torque loadings a modern V8 or supercharged V6 Land Rover produces.
A typical front or rear differential service on a Discovery 3, Discovery 4, Range Rover L322 or Range Rover Sport requires approximately 1.0 litre per axle, with the exact figure depending on housing variant and any modifications. The factory service interval for differential oil is generally 105,000 miles or every six years under normal conditions, though shorter intervals are advisable on cars used for regular towing, off-road work or wading. Browse our Castrol axle oils range for related Castrol axle oils, including SAF-XJ for limited-slip differential applications, and our transfer box and differential fluid listings for full coverage of related Land Rover transmission lubricants.
The full Castrol range at Rimmer Bros covers engine oils, gear oils, brake fluids and transmission fluids across the entire JLR application set, and our oils and lubricants section extends across other Castrol grades plus alternative brands where appropriate. For the broader maintenance picture on these cars, our Land Rover car parts and Range Rover car parts sections carry service kits, filters, brake components and suspension parts for every variant covered by TYK500010.
Founded in Lincoln in 1982, we have been supplying genuine and OEM Land Rover parts to owners and specialists in the UK and 195 countries worldwide for over two decades. Our parts team can confirm the correct differential oil specification and quantity for your specific car. Call us on 01522 568000 before ordering if your car has a locking differential or if you are unsure of the variant fitted.
Order Castrol SAF-XO TYK500010 online at Rimmer Bros for fast, worldwide dispatch from our warehouse in Lincoln.