Robust Formula Provides Long-Lasting Protection in Severe Service, including High & Low Temperatures

Monolec® Syn All-Climate Gear Lubricant (9919-9920) is formulated with 100 percent synthetic base fluid and a synergistic additive package, making it the ideal choice for heavy-duty rolling stock transmissions and differentials in severe service conditions. It is also recommended for some high- and low-temperature industrial gearbox applications. Monolec Syn All-Climate's robust formula will not break down in severe service. It provides high-temperature oxidation resistance, low volatility and excellent thermal stability, allowing it to provide long-lasting protection for the application. It also retains its flow during subzero temperature conditions. The additive package includes wear-reducing, extreme pressure (EP) and anti-foaming additives.

Lubrication Engineers operates under an ISO 9001 Certified Quality System.

Unit of Measure

Benefits and Recommendations

Available Container Size

N/A Drum

GHS Statement

N/A For commercial and professional use only

Beneficial Qualities


Delivers Exceptional Limited
Slip Performance

  • Eliminates “chatter” or “squawk”
    that results from improper
    lubrication of limited slip
  • Provides smooth engagement of
    friction plates
  • Maintains limited slip
    performance throughout life of oil

Provides Reliable, Long-Lasting Service

  • Resists shearing and maintains
    viscosity in service
  • Remains thermally stable
  • Prevents formation of carbon deposits
  • Reduces operating temps by
    transferring heat from gears
  • Protects gears from wear, heavy
    loads and shock loading
  • Increases equipment reliability,
    reducing replacement and
    repair costs
  • Suppresses foam

Performs in High
and Low Temperatures

  • Extends drain intervals due to long oil life
  • Requires less make-up oil due to low volatility
  • Reduces environmental impact with less waste oil for disposal
  • Reduces maintenance and
    replacement costs by reducing wear

Proprietary Additive


LE’s proprietary additives are used exclusively in LE lubricants. Monolec®
Syn Gear Oil contains Monolec.

Monolec® wear-reducing additive creates a single molecular lubricating film on metal surfaces, vastly increasing oil film strength without affecting clearances. An invaluable component in LE’s engine oils, industrial oils and many of its other lubricants, Monolec allows opposing surfaces to slide by one another, greatly reducing friction, heat and wear. 

Performance Requirements Met or Exceeded

  • API GL-5
  • API MT-1
  • Service Fill Limited Slip
  • USDA H2
  • ZF TE-ML 07A
  • ZF TE-ML 08

Typical Applications

  • Differentials & non-synchronized transmissions in:
    • Over-the-road fleets
    • Off-highway equipment
    • Stop-and-go vehicles
    • All trucks that fall within the DOT Gross Vehicle
      Weight Rating of Class 1 to Class 6.
  • Industrial gearboxes and worm drives that:
    • Call for SAE 75W-90 gear oil (9919)
    • Call for SAE 75W-140 gear oil (9923)
    • Are subjected to low and/or high temperatures

Asset Reliability Solutions

N/A Reliability Solution Products

Physical Characteristics - Typical


N/A Green

SAE Grade

N/A 75W-90

Performance Test Results

Relative Density @ 60ºF/60ºF, ASTM D1298

N/A 0.871

Viscosity @ 100°C, cSt, ASTM D445

N/A 15.0

Viscosity @ 40°C, cSt, ASTM D445

N/A 100.0

Viscosity Index ASTM D2270

N/A 157

Viscosity-Brookfield @ -40ºC, cP, ASTM D2983

N/A ≤50,000

Flash Point °C (°F), (COC), ASTM D92

N/A 226 (429)

Pour Point °C (°F), ASTM D97

N/A -54 (-65)

Copper Corrosion 3 hrs @ 100ºC, ASTM D130

N/A 1b

Timken OK Load lbs, ASTM D2782

N/A 90

FZG Scuffing Load Capacity Fail Stage, ASTM D5182

N/A >12