AUTHORIZED
Motul 105777 Gear 300 75W-90 is a synthetic-technology gear oil for high-load gearboxes and differentials that call for a 75W-90 gear lubricant meeting API GL-4/GL-5 and MIL-L 2105 D. It uses an ester-based formulation with extreme-pressure protection to maintain a stable oil film between gear teeth under shock loading while staying fluid enough for cold shifting.
Quick Answer: Motul 105777 is intended for mechanical gearboxes and differentials operating under heavy load, including synchronized or non-synchronized gearsets, when the application specifies a 75W-90 gear oil meeting API GL-4/GL-5 and MIL-L 2105 D. It is not intended for limited slip differentials, since those units typically require a friction-modified gear oil.
Gear 300 is positioned for performance-driven use where gear tooth contact stress and heat are the limiting factors, such as track days, rally-style duty cycles, or street cars that see sustained load. The viscosity profile and additive package are designed to resist thinning under shear and protect hypoid and helical gear meshes without turning the fluid into a cold-weather brick.
Compared with a conventional gear oil that can shear down in hard use, the Gear 300 75W-90 emphasizes film stability and wear protection under shock loads so the gearbox and final drive stay protected when temperatures and torque spikes climb.
Ideal for high-load mechanical transmissions and differentials that specify 75W-90 GL-4/GL-5; not intended for limited slip differentials or applications that require friction-modified LSD fluid.
Key Specs Snapshot
| Viscosity grade | SAE 75W-90 |
|---|---|
| Density | 0.897 at 20 C |
| Viscosity at 40 C | 86.5 mm2/s |
| Viscosity at 100 C | 14.2 mm2/s |
| Viscosity Index | 170 |
| Pour point | -54 C |
| Flash point | 204 C |
Yes, it is intended for mechanical transmissions, including synchronized gearboxes, when the application specifies a 75W-90 gear oil meeting GL-4/GL-5 performance requirements.
It is intended for hypoid differentials without a limited slip system when the service specification calls for a 75W-90 GL-4/GL-5 gear oil.
Follow the vehicle manufacturer procedure for drain and fill sequence, fill-point temperature, and level check method. As a practical check, keep the vehicle level during the final fill and confirm the fluid reaches the factory fill reference point before reinstalling the fill plug. After the first short drive, recheck for seepage at the drain and fill plugs so small sealing issues are caught early.
Use the fluid specification listed for the specific component you are servicing, not a generic drivetrain guess. Many vehicles use different fluids between the manual gearbox, front differential, rear differential, and transfer case, even within the same platform. Match the required viscosity grade (75W-90) and the performance requirement (GL-4, GL-5, or both) to the service manual or factory service information for that component before filling.
GL categories describe the lubricant performance level needed for different gear contact conditions and additive demands. In practice, many gearboxes and hypoid gearsets call for a fluid that can handle high load and sliding contact while still supporting gearbox operation, so a product formulated to meet both categories can cover a broader set of mechanical transmission and differential requirements. Always follow the component specification first.
Fluid choice can change cold shift effort and how gear noise is transmitted through the case, especially when viscosity and film strength differ from what is currently in the unit. Gear 300 is designed to remain fluid at lower temperatures and maintain film resistance under load, which can help stabilize feel in demanding use. If your differential is limited slip and you notice chatter, this product is not intended for that application.
SKU:105777-AWD ,UPC: ,Condition: ,Availability:
Motul
