Product selection
By MAXILUB Technical Team · 5 min read · Published · Updated
GL-4 and GL-5 are performance categories
API GL-4 and GL-5 describe different gear-lubricant service categories. They are not viscosity grades and should not be treated as interchangeable labels. The equipment manufacturer determines the required category. A product carrying GL-5 should not automatically be used where GL-4 is specified unless the product and equipment documentation explicitly support that use.
Match the SAE viscosity too
A gear oil requirement usually combines a service category with an SAE viscosity such as 75W-90, 80W-90 or 85W-140. The same service category can be available in several viscosities. Confirm both values from the manual, equipment label or service documentation before requesting a quote.
Manual transmissions and axles can differ
A truck, machine or vehicle may specify one lubricant for the transmission and another for the axle or final drive. Synchronizer materials, gear geometry and operating load can affect the requirement. Build an asset-specific lubricant chart so purchasing and maintenance teams do not assume that one gear oil covers every compartment.
What to send the distributor
Provide the required API category, SAE viscosity, equipment type, any OEM specification, quantity, package size and delivery ZIP code. If the requirement is unclear, send a photo or exact transcription of the manual specification rather than relying on a product color or brand previously used.
Related catalog paths
Apply this guidance to current product listings.
Use the guide as a comparison framework, then review the verified signals and available product data sheet on each listing.
Gear Oils
Ultra1Plus SAE 50 Transmission Drivetrain Torque Fluid, TO-4
Review product details and PDS
Gear Oils
Ultra1Plus SAE 140 Conventional Gear Oil
Review product details and PDS
Gear Oils
Ultra1Plus SAE 85W-140 Conventional Gear Oil
Review product details and PDS
Gear Oils
Ultra1Plus EP ISO 220 Conventional Gear Oil
Review product details and PDS