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Steel Shield Automotive Gears Lubricants are the ultimate protector and energy saver for any gearing system. Gear contacting faces and bearings are treated by unique ABF Technology which enhance the surface hardness and smoothness. The result are: gears last much much longer and energy consumption drop to the minimum. Steel Shield lubricants DO NOT contain any solid additives which can damage your precious gears, because ABF Technology is more advanced than most of the premium lubricants in the market.

Automotive Gear Lubricants

The following inducates the general applications of automotive gears which includes all the spur, helical, spiral bevel, hypoid and planetary gear types:

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  • Automotive Transmissions
    • Light Duty: Cars and light trucks
    • Heavy Duty: Commercial trucks, e.g. Allison
  • Power Transmissions: e.g. Caterpillar, Clark
  • Manual Transmissions
    • Light Duty: Synchronized
    • Heavy Duty: Mainly non-synchronized
  • Transaxles: Front wheel drive vehicles
  • Transfer Cases: Four wheel drive vehicles
  • Differentials: Hypoid gears
  • Final Drives: Planetary gears
  • Tractor / Wet Brake Applications
The 6 General Automotive Lubricant Types And Applications
Lubricant Applications
1 Automatic Transmission Fluid (ATF) Automatic transmissions and some transfer cases
2 Non Extreme Pressure (R&O) Gear Oil Heavy duty manual transmissions
3 Full Extreme Pressure (EP) Gear Oil Differentials, final drives, transfer cases & manual transmissions
4 Engine Oils Manual transmissions
5 CAT TO-4 Fluids Caterpillar transmissions and hydraulics
CAT FDAO Fluids Off-highway Caterpillar final drive, differentials and axle components
6 Universal Tractor Fluids Common sump (transmissions, wet brake and hydraulics) of agricultural tractors

API Service Designation

The API Gear Lubricant "GL" designation classify automotive gear lubricants which relates to the automotive gear service. Notice that the GL designations do not included all the automotive gear appications mentioned above and no performance tests are carried out to classisfy the lubricants. Notice that GL-5 lubricants have much higher concentration of extreme pressure (EP) additive than a typical industrial EP gear oil (upwards of 4 times). So, industrial gear lubricants cannot be used in automotive applications. Also, limited slip differentials require a special additive to be present in the lubricant. Conventional GL-5 gear lubricants can only be used to top-up (not refill) limited slip differentials. Here is the short list of API designations:

API GL Designations Not In Current Use
Designation Applications
  • Mild automotive spiral bevel & worm gear axles, and some manual transmissions
  • Mineral oil with rust & oxidation inhibitors
  • No friction modifiers or extreme pressure (EP) additives
  • For automotive worm-gear axles
  • Anti-wear or very mild extreme pressure
  • Usually contains fatty additives
  • Manual transmissions and spiral bevel axles
  • No hypoid gears
  • Moderately severe speed and load
  • Mild extreme pressure (EP)
  • Older designation to reduce gear scuffing during high powered, full throttle starts
API GL Designations Currently Using
Designation Applications
  • Moderate service, non-critical, manual transmissions, spiral bevel and hypoid gears
  • Primary field service recommendation for most passenger cars and trucks

API Service Designation Beyond GL

API GL designations do not included all the automotive gear applications. Several heavy truck manufacturers defined their own specifications (e.g. Allison C-4, Caterpiller TO-4, and TO-2, Mack TO-A. etc.). These may require special lubricants or may be met by (non-EP) diesel engine oils (e.g. CJ-4) or ATFs. Here reviewed some examples of designations:

API Designations Beyond GL
Designation Applications
  • For non-synchronized manual transmissions used in buses and heavy-duty trucks
  • Meets API MT-1 provide protection against the combination of thermal degradation, component wear, and oil seal deterioration which is not provided by lubricants meeting only the requirements of API GL-4 and API GL-5.
  • Combines the performance requirements of its predecessor (MIL-L-2105D) and API MT-1
  • Maintains all existing chemical/physical requirements, stationary axle test requirements, field test requirements and data review by the Lubricants Review Institute that were required under MIL-L-2105D.
  • Added the stringent oil seal compatibility and thermal durability test requirements under API MT-1
  • Has been re-written as SAE Standard J2360.
SAE J2360
  • A new global quality standard that defines a level of performance equivalent to that defined by MIL-PRF-2105E
  • A U.S. military standard for approval that was not available to oil blenders in all parts of the world
  • Included all of the most recent axle and transmission testing requirements identified in API GL-5, API MT-1, and MIL-PRF-2105E including the need to demonstrate proof-of-performance through rigorous field testing.

API Service Designation Summary

Always check the owner's manuals for automatic transmission lubricant recommendations and consult the manufacturers when necessary.

Lubricants And Designations Summary
Designation Applications
Automatic Transmission Fluid (ATF) Generally meets D3M and C-4 and TO-2, or Mercon V®, or Dexron VI®, or Mopar ATF+4®
Non Extreme Pressure (R&O) Gear Oil Generally GL-1 and MIL 2104
Full Extreme Pressure (EP) Gear Oil Generally GL-5, GL-4, MIL-PRF-2105E, Mack GO-J, and MT-1
Engine Oils Generally CJ-4, SM, TO-2, C-4
CAT TO-4 Fluids TO-4, TO-2 and GL-3
Universal Tractor Fluids Generally TO-2, John Deere J20C (summer) and J20D (winter), and New Holland FNH 200 (all season)

SAE Viscosity Grade Classifications For Automotive Gear Oils

The SAE viscosity grades are based on the lubricant viscosity measurements at both high and low temperatures. The high temperature (100℃) kinematic viscosities tests can ensure the mechanical components have adequate lubricant film thickness in order to prevent wearings. The low temperature (-12℃, -26℃, -40℃ and -55℃) viscosities measures by the Brookfield tests ensure there is enough lubricant flowability to avoid components damage in low temperature cold-start conditions.

SAE J306 Automotive Gear Lubricant Classification (200506)
SAE Viscosity Grade Max Temperature for Viscosity of 150,000 cP(℃)(1,2) Kinematic Viscosity at 100℃ (cSt)(3)
Min(4) Max
70W -55(5) 4.1
75W -40 4.1
80W -26 7.0
85W -12 11
80 7.0 <11
85 11 <13.5
90 13.5 <18.5
110 18.5 <24.0
140 24 <32.5
190 32.5 <41.0
250 41.0


  1. Using ASTM D2983
  2. Additional low-temperature viscosity requirements may be appropriate for fluids
  3. Using ASTM D445
  4. Limite must also be met after testing in CEC L-45-T-93, Method C (20 hours)
  5. The precision of ASTM D2983 has not been established for determinations made at temperatures below -40℃. This fact should be taken into consideration in any producer-consumer relationship

Learn More About Engine Oils:

Engine Oils