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

Monolec® Syn Gear Oil (9919 & 9923) is a 100 percent synthetic, limited slip gear oil with a high-performance additive package, making it an ideal choice for transmissions and differentials that encounter severe service conditions, including fleets of delivery trucks, heavy-duty pickup trucks, school buses, and bucket trucks. Its high-performance formula will not break down in severe service. It resists gear and bearing wear, viscosity loss, foaming, high-temperature oxidation, and volatility, allowing it to deliver long-lasting protection for any application where extreme pressure and shock loading is expected, including industrial gearboxes that require enhanced EP protection.

In addition, Monolec Syn Gear Oil’s high-performance formula features a high viscosity index and low pour point that work together to provide hightemperature
film thickness and low-temperature fluidity, allowing it to be used in a wide range of environments – from very hot to below freezing.

Unit of Measure

Benefits and Recommendations

Available Container Size

N/A Pail

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

  • Provides high-temperature oxidation resistance
  • Is reliable for low-temperature startups
  • Flows well at below freezing

Reduces Oil Consumption
& Other Costs

  • 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 & 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 high temperatures

Asset Reliability Solutions

N/A Reliability Solution Products

Physical Characteristics - Typical


N/A Green

SAE Grade

N/A 75W-140

Performance Test Results

Relative Density @ 60ºF/60ºF, ASTM D1298

N/A 0.891

Viscosity @ 100°C, cSt, ASTM D445

N/A 26.0

Viscosity @ 40°C, cSt, ASTM D445

N/A 190.0

Viscosity Index ASTM D2270

N/A 171

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

N/A ≤150,000

Flash Point °C (°F), (COC), ASTM D92

N/A 220 (428)

Pour Point °C (°F), ASTM D97

N/A -45 (-49)

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