Castrol Syntrax 80W-140 is a full synthetic rear axle fluid designed to provide protection at the extremes of low and high operating temperatures. It is particularly recommended for competition, severe duty and long drain applications. It may be used in both limited slip and non limited slip differentials. Particular applications include Holden V8 rear axles, trucks operating in severe service where high temperatures in differentials and power dividers are encountered, and competition vehicles such as sports sedans and rally cars.

Suitable for use where SAE 80W-140 or 85W-140 API GL-5 is required, with or without limited slip performance. Approved to (former) BTR/Dana Australia 5M-48 performance specification.

Advantages:
- Excellent high temperature and load performance provides maximum protection against wear and noise
- Low friction improves axle efficiency offering fuel economy improvements
- Highly shear stable ensuring properties are retained over very long service periods
- Reduced operating temperatures increase life of gears and seals
- Wide viscosity range ensures suitability for use in all temperatures
- Compatible with mineral gear oils and seals so it may replace conventional oils with no need for seal changes or extensive flushing