Castrol Syngear 75W-90 is a full-synthetic gear oil used in heavy duty Class 8 trucks. This unique product delivers an impressive set of approvals:
By definition, a 75W-90 gear oil will provide better fuel economy than an 80W-90 or 75W-140 fluid, but Castrol Syngear 75W-90 was re-engineered to take its fuel-economy performance to an even higher level while maintaining all other approvals and characteristics.
Changes include reduced high and low temperature viscosity, improved shear stability, and the product is now a darker amber color versus the original light-yellow version. The additive package has been modified to keep gear protection and all other performance at the same level even though the viscosity has been reduced.
The new formulation provides up to a 1% fuel economy improvement versus the prior Castrol Syngear 75W-90 product, as well as other competitive 75W-90 and 80W-90 GL-5 gear oils. This fuel economy advantage was demonstrated using Class 8 line haul trucks in three separate high-load and high-speed field tests using SAE J1321, J1376, and J1526 test methods.
The SAE J1321 testing was done in hilly conditions near San Antonio, TX. The Modified SAE J1526 testing was performed using a fleet near Green Bay, WI, and the SAE J1376 testing was done in the hilly region near Gila Bend, AZ.
The 1% fuel economy improvement translates to $810 in yearly savings per truck (based on 120,000 miles, 5.5 mpg, $3.73 per gal fuel) and $4,050 over a 5- year warranty period.