Several types of lubricating grease are needed to properly lubricate a heavy duty (Class 8 in the US) truck:
Wheel bearing grease â€“ Some wheel bearings are â€œlubed for lifeâ€ while others require regular relubrication. Unless the wheel bearings are â€œlubed for life,â€ they should be relubricated at the interval recommended by the OEM. The OEM should provide guidelines for the consistency and grease thickener type that was originally installed in the bearings. The grease used for most wheel bearings should meet the NLGI GC-LB requirements or the SAE J2695 requirements. Most wheel bearings require an NLGI 2 grade grease, while some sealed hub units require an NLGI 00 grade semi-fluid product. For those cases, the NLGI GC-LB or SAE J2695 consistency requirements do not apply. Each type is unique to the bearing design, and should not be used in the other type of bearing.
Chassis and universal joint grease â€“ The grease used for the lubrication of chassis points and universal joints is often the same as the wheel bearing grease. However, if the wheel bearings require an NLGI 00 grade semi-fluid grease, the chassis and universal joint grease will be different. It should meet the NLGI GC-LB or SAE J2695 requirements.
Fifth wheel grease â€“ Fifth wheels require a specific grease, different from the wheel bearings or chassis points. The grease for the fifth wheel is typically a water resistant product with a relatively high concentration of solid additives, such as molybdenum disulfide or graphite. This allows the metal-to-metal sliding contact to be properly lubricated.