Viscosity of Gear Oils
SAE 75W-140 synthetic HD gear oil
Description
Gear oil is a special lubricant for transmissions and differentials in cars, trucks and machinery. Manual gearboxes and differentials use rather highly viscous hypoid gear oils compared to engine oils. Gearboxes do not have an oil pump, so the high viscosity is needed to distribute the oil and to keep it on the metal surfaces, as only the lowermost part of the gears is located in the oil sump.
Depending on the type, these oils contain different amounts of extreme pressure and antiwear additives. The viscosity grades of gear oils are specified according to the SAE Standard J 306. The API (American Petroleum Institute) divides gear oils into 6 classes.
Viscosity Table – Measurement data
SAE 75W-140
| Temp. [°C] | Dyn. Viscosity [mPa.s] | Kin. Viscosity [mm²/s] | Density [g/cm³] |
|---|---|---|---|
| 0 | 1551.5 | 1792.6 | 0.8655 |
| 10 | 768.20 | 894.09 | 0.8592 |
| 20 | 410.55 | 481.38 | 0.8529 |
| 30 | 236.53 | 279.38 | 0.8466 |
| 40 | 145.40 | 173.00 | 0.8404 |
| 50 | 94.468 | 113.24 | 0.8342 |
| 60 | 64.333 | 77.695 | 0.8280 |
| 70 | 45.654 | 55.561 | 0.8217 |
| 80 | 33.544 | 41.137 | 0.8154 |
| 90 | 25.409 | 31.399 | 0.8092 |
| 100 | 19.749 | 24.591 | 0.8031 |
Gear oil SAE 75W-140 - kinematic viscosity and density over temperature
Reference
Measured with SVM™.
Metainformation
| Reference | Measurement with SVM™ |
|---|---|
| Kin. vis. | yes |
| Dyn. vis. | yes |
| Density | yes |
| Multiple temperatures | yes |
| Related | Lubricant, lube, gear oil, hypoid oil, viscosity, SAE |